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  • Life Sciences (General)  (2,488)
  • Protein Conformation
  • 2000-2004  (2,714)
  • 1980-1984  (106)
  • 1935-1939
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  • 1
    Publication Date: 2004-06-05
    Description: The mechanisms by which hydrophobic molecules, such as long-chain fatty acids, enter cells are poorly understood. In Gram-negative bacteria, the lipopolysaccharide layer in the outer membrane is an efficient barrier for fatty acids and aromatic hydrocarbons destined for biodegradation. We report crystal structures of the long-chain fatty acid transporter FadL from Escherichia coli at 2.6 and 2.8 angstrom resolution. FadL forms a 14-stranded beta barrel that is occluded by a central hatch domain. The structures suggest that hydrophobic compounds bind to multiple sites in FadL and use a transport mechanism that involves spontaneous conformational changes in the hatch.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉van den Berg, Bert -- Black, Paul N -- Clemons, William M Jr -- Rapoport, Tom A -- New York, N.Y. -- Science. 2004 Jun 4;304(5676):1506-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA. lvandenberg@hms.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15178802" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Bacterial Outer Membrane Proteins/*chemistry/metabolism ; Binding Sites ; Biological Transport ; Crystallization ; Crystallography, X-Ray ; Escherichia coli/chemistry/metabolism ; Escherichia coli Proteins/*chemistry/metabolism ; Fatty Acid Transport Proteins ; Fatty Acids/*metabolism ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Models, Biological ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary
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    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2004-01-06
    Description: MDM2 binds the p53 tumor suppressor protein with high affinity and negatively modulates its transcriptional activity and stability. Overexpression of MDM2, found in many human tumors, effectively impairs p53 function. Inhibition of MDM2-p53 interaction can stabilize p53 and may offer a novel strategy for cancer therapy. Here, we identify potent and selective small-molecule antagonists of MDM2 and confirm their mode of action through the crystal structures of complexes. These compounds bind MDM2 in the p53-binding pocket and activate the p53 pathway in cancer cells, leading to cell cycle arrest, apoptosis, and growth inhibition of human tumor xenografts in nude mice.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vassilev, Lyubomir T -- Vu, Binh T -- Graves, Bradford -- Carvajal, Daisy -- Podlaski, Frank -- Filipovic, Zoran -- Kong, Norman -- Kammlott, Ursula -- Lukacs, Christine -- Klein, Christian -- Fotouhi, Nader -- Liu, Emily A -- New York, N.Y. -- Science. 2004 Feb 6;303(5659):844-8. Epub 2004 Jan 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Discovery Oncology, Roche Research Center, Hoffmann-La Roche, Inc., Nutley, NJ 07110, USA. lyubomir.vassilev@roche.com〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14704432" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Apoptosis/*drug effects ; Binding Sites ; Cell Cycle/drug effects ; Cell Division/*drug effects ; Cell Line ; Cell Line, Tumor ; Cell Survival/drug effects ; Crystallization ; Crystallography, X-Ray ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins/metabolism ; Dose-Response Relationship, Drug ; Gene Expression ; Genes, p53 ; Humans ; Hydrophobic and Hydrophilic Interactions ; Imidazoles/chemistry/metabolism/*pharmacology ; Mice ; Mice, Nude ; Models, Molecular ; Molecular Weight ; NIH 3T3 Cells ; Neoplasm Transplantation ; Neoplasms, Experimental/drug therapy/metabolism/*pathology ; *Nuclear Proteins ; Phosphorylation ; Piperazines/chemistry/metabolism/*pharmacology ; Protein Conformation ; Proto-Oncogene Proteins/*antagonists & inhibitors/chemistry/metabolism ; Proto-Oncogene Proteins c-mdm2 ; Stereoisomerism ; Transplantation, Heterologous ; Tumor Suppressor Protein p53/*metabolism
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  • 3
    Publication Date: 2004-11-30
    Description: Polycomb group proteins preserve body patterning through development by maintaining transcriptional silencing of homeotic genes. A long-standing hypothesis is that silencing involves creating chromatin structure that is repressive to gene transcription. We demonstrate by electron microscopy that core components of Polycomb Repressive Complex 1 induce compaction of defined nucleosomal arrays. Compaction by Polycomb proteins requires nucleosomes but not histone tails. Each Polycomb complex can compact about three nucleosomes. A region of Posterior Sex Combs that is important for gene silencing in vivo is also important for chromatin compaction, linking the two activities. This mechanism of chromatin compaction might be central to stable gene silencing by the Polycomb group.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Francis, Nicole J -- Kingston, Robert E -- Woodcock, Christopher L -- GM43786/GM/NIGMS NIH HHS/ -- NIH-P41-RR01777/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2004 Nov 26;306(5701):1574-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15567868" target="_blank"〉PubMed〈/a〉
    Keywords: Chromatin/*chemistry/metabolism/ultrastructure ; DNA/*chemistry/metabolism ; Gene Expression Regulation ; Gene Silencing ; HeLa Cells ; Histones/*chemistry/metabolism ; Humans ; Microscopy, Electron ; Microscopy, Electron, Scanning ; Nucleosomes/*chemistry/metabolism/ultrastructure ; Polycomb-Group Proteins ; Protein Conformation ; Repressor Proteins/*chemistry/metabolism
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2004-02-07
    Description: The 1918 influenza pandemic resulted in about 20 million deaths. This enormous impact, coupled with renewed interest in emerging infections, makes characterization of the virus involved a priority. Receptor binding, the initial event in virus infection, is a major determinant of virus transmissibility that, for influenza viruses, is mediated by the hemagglutinin (HA) membrane glycoprotein. We have determined the crystal structures of the HA from the 1918 virus and two closely related HAs in complex with receptor analogs. They explain how the 1918 HA, while retaining receptor binding site amino acids characteristic of an avian precursor HA, is able to bind human receptors and how, as a consequence, the virus was able to spread in the human population.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gamblin, S J -- Haire, L F -- Russell, R J -- Stevens, D J -- Xiao, B -- Ha, Y -- Vasisht, N -- Steinhauer, D A -- Daniels, R S -- Elliot, A -- Wiley, D C -- Skehel, J J -- AI-13654/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 2004 Mar 19;303(5665):1838-42. Epub 2004 Feb 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Medical Research Council (MRC) National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14764886" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Binding Sites ; Birds ; Crystallography, X-Ray ; Hemagglutinin Glycoproteins, Influenza Virus/*chemistry/*metabolism ; History, 20th Century ; Humans ; Hydrogen Bonding ; Influenza A virus/*immunology/metabolism/pathogenicity ; Influenza, Human/epidemiology/history/*virology ; Membrane Glycoproteins/chemistry/metabolism ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Structure, Tertiary ; Receptors, Virus/*metabolism ; Sequence Alignment ; Sialic Acids/metabolism ; Species Specificity ; Swine
    Print ISSN: 0036-8075
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  • 5
    Publication Date: 2004-12-04
    Description: DNA photolyases use light energy to repair DNA that comprises ultraviolet-induced lesions such as the cis-syn cyclobutane pyrimidine dimers (CPDs). Here we report the crystal structure of a DNA photolyase bound to duplex DNA that is bent by 50 degrees and comprises a synthetic CPD lesion. This CPD lesion is flipped into the active site and split there into two thymines by synchrotron radiation at 100 K. Although photolyases catalyze blue light-driven CPD cleavage only above 200 K, this structure apparently mimics a structural substate during light-driven DNA repair in which back-flipping of the thymines into duplex DNA has not yet taken place.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mees, Alexandra -- Klar, Tobias -- Gnau, Petra -- Hennecke, Ulrich -- Eker, Andre P M -- Carell, Thomas -- Essen, Lars-Oliver -- New York, N.Y. -- Science. 2004 Dec 3;306(5702):1789-93.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Biochemistry, Butenandt-Strasse 5-13, Ludwig Maximilians University, D-81377 Munich, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15576622" target="_blank"〉PubMed〈/a〉
    Keywords: Base Pairing ; Binding Sites ; Crystallization ; Crystallography, X-Ray ; DNA/*chemistry/metabolism ; *DNA Damage ; *DNA Repair ; DNA, Single-Stranded/chemistry/metabolism ; Deoxyribodipyrimidine Photo-Lyase/*chemistry/metabolism ; Flavin-Adenine Dinucleotide/metabolism ; Hydrogen Bonding ; Nucleic Acid Conformation ; Protein Conformation ; Pyrimidine Dimers/*chemistry/metabolism ; Synechococcus/*enzymology ; Thymine/chemistry
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    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2004-05-25
    Description: The protein-remodeling factor Hsp104 governs inheritance of [PSI+], a yeast prion formed by self-perpetuating amyloid conformers of the translation termination factor Sup35. Perplexingly, either excess or insufficient Hsp104 eliminates [PSI+]. In vitro, at low concentrations, Hsp104 catalyzed the formation of oligomeric intermediates that proved critical for the nucleation of Sup 35 fibrillization de novo and displayed a conformation common among amyloidogenic polypeptides. At higher Hsp104 concentrations, amyloidogenic oligomerization and contingent fibrillization were abolished. Hsp104 also disassembled mature fibers in a manner that initially exposed new surfaces for conformational replication but eventually exterminated prion conformers. These Hsp104 activities differed in their reaction mechanism and can explain [PSI+] inheritance patterns.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shorter, James -- Lindquist, Susan -- GM25874/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jun 18;304(5678):1793-7. Epub 2004 May 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15155912" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/metabolism ; Amyloid/chemistry ; Amyloid beta-Peptides/chemistry/immunology ; Antibodies/immunology ; Biopolymers ; Catalysis ; Heat-Shock Proteins/chemistry/genetics/*metabolism ; Hydrolysis ; Mutation ; Peptide Fragments/chemistry/immunology ; Peptide Termination Factors ; Prions/*chemistry/*metabolism ; Protein Conformation ; Protein Structure, Tertiary ; Saccharomyces cerevisiae Proteins/*chemistry/genetics/*metabolism
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  • 7
    Publication Date: 2004-10-02
    Description: A stable phase of toroidal, or ringlike, supramolecular assemblies was formed by combining dilute solution characteristics critical for both bundling of like-charged biopolymers and block copolymer micelle formation. The key to toroid versus classic cylinder micelle formation is the interaction of the negatively charged hydrophilic block of an amphiphilic triblock copolymer with a positively charged divalent organic counterion. This produces a self-attraction of cylindrical micelles that leads to toroid formation, a mechanism akin to the toroidal bundling of semiflexible charged biopolymers such as DNA. The toroids can be kinetically trapped or chemically cross-linked. Insight into the mechanism of toroid formation can be gained by observation of intermediate structures kinetically trapped during film casting.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pochan, Darrin J -- Chen, Zhiyun -- Cui, Honggang -- Hales, Kelly -- Qi, Kai -- Wooley, Karen L -- New York, N.Y. -- Science. 2004 Oct 1;306(5693):94-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Materials Science and Engineering and Delaware Biotechnology Institute, University of Delaware, Newark, DE 19716, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15459386" target="_blank"〉PubMed〈/a〉
    Keywords: Acrylates/chemistry ; Acrylic Resins/chemistry ; Actins/chemistry ; Biopolymers/chemistry ; DNA/chemistry ; Diethylamines/chemistry ; Furans/chemistry ; Hydrophobic and Hydrophilic Interactions ; *Micelles ; Molecular Structure ; Nucleic Acid Conformation ; Polymers/*chemistry ; Protein Conformation ; Styrene/chemistry
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  • 8
    Publication Date: 2004-02-14
    Description: The structure of an RNA polymerase II-transcribing complex has been determined in the posttranslocation state, with a vacancy at the growing end of the RNA-DNA hybrid helix. At the opposite end of the hybrid helix, the RNA separates from the template DNA. This separation of nucleic acid strands is brought about by interaction with a set of proteins loops in a strand/loop network. Formation of the network must occur in the transition from abortive initiation to promoter escape.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Westover, Kenneth D -- Bushnell, David A -- Kornberg, Roger D -- GM49985/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Feb 13;303(5660):1014-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14963331" target="_blank"〉PubMed〈/a〉
    Keywords: Base Pairing ; Crystallization ; Crystallography, X-Ray ; DNA, Single-Stranded/*chemistry/metabolism ; Models, Molecular ; Nucleic Acid Conformation ; Nucleic Acid Hybridization ; Oligodeoxyribonucleotides/chemistry/metabolism ; Oligoribonucleotides/chemistry/metabolism ; Promoter Regions, Genetic ; Protein Conformation ; RNA Polymerase II/*chemistry/*metabolism ; RNA, Complementary/*chemistry/metabolism ; Saccharomyces cerevisiae/enzymology ; Templates, Genetic ; Transcription Factor TFIIB/metabolism ; *Transcription, Genetic
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    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-01-06
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wickelgren, Ingrid -- New York, N.Y. -- Science. 2004 Jan 2;303(5654):28-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14704404" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Aplysia/physiology ; Memory/*physiology ; Neurons/*physiology ; Prions/chemistry/metabolism/*physiology ; Protein Biosynthesis ; Protein Conformation ; RNA, Messenger/genetics/metabolism ; Solubility ; Transcription Factors/chemistry/genetics/*metabolism ; Yeasts/genetics/metabolism ; mRNA Cleavage and Polyadenylation Factors/chemistry/genetics/*metabolism
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  • 10
    Publication Date: 2004-01-24
    Description: Unlike major histocompatibility proteins, which bind peptides, CD1 proteins display lipid antigens to T cells. Here, we report that CD1a presents a family of previously unknown lipopeptides from Mycobacterium tuberculosis, named didehydroxymycobactins because of their structural relation to mycobactin siderophores. T cell activation was mediated by the alphabeta T cell receptors and was specific for structure of the acyl and peptidic components of these antigens. These studies identify a means of intracellular pathogen detection and identify lipopeptides as a biochemical class of antigens for T cells, which, like conventional peptides, have a potential for marked structural diversity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Moody, D Branch -- Young, David C -- Cheng, Tan-Yun -- Rosat, Jean-Pierre -- Roura-Mir, Carme -- O'Connor, Peter B -- Zajonc, Dirk M -- Walz, Andrew -- Miller, Marvin J -- Levery, Steven B -- Wilson, Ian A -- Costello, Catherine E -- Brenner, Michael B -- AI30988/AI/NIAID NIH HHS/ -- AI50216/AI/NIAID NIH HHS/ -- AR48632/AR/NIAMS NIH HHS/ -- CA58896/CA/NCI NIH HHS/ -- GM25845/GM/NIGMS NIH HHS/ -- GM62116/GM/NIGMS NIH HHS/ -- P20 RR16459/RR/NCRR NIH HHS/ -- P41-RR10888/RR/NCRR NIH HHS/ -- S10-RR10493/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2004 Jan 23;303(5657):527-31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School, Smith Building Room 514, 1 Jimmy Fund Way, Boston, MA 02115, USA. bmoody@rics.bwh.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14739458" target="_blank"〉PubMed〈/a〉
    Keywords: *Antigen Presentation ; Antigens, Bacterial/chemistry/*immunology/metabolism ; Antigens, CD1/chemistry/immunology/metabolism ; Cell Line ; Chromatography, High Pressure Liquid ; Humans ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Hydroxylation ; Lipoproteins/chemistry/*immunology/metabolism ; *Lymphocyte Activation ; Models, Molecular ; Mycobacterium tuberculosis/growth & development/*immunology ; Oxazoles/chemistry/*immunology/metabolism ; Protein Conformation ; Receptors, Antigen, T-Cell, alpha-beta/immunology ; T-Lymphocytes/*immunology ; Transfection
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  • 11
    Publication Date: 2004-10-30
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wickelgren, Ingrid -- New York, N.Y. -- Science. 2004 Oct 29;306(5697):791-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15514121" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid beta-Peptides/*chemistry/metabolism/toxicity ; Animals ; Cell Death/drug effects ; Cells, Cultured ; Congo Red/*analogs & derivatives/*chemical ; synthesis/chemistry/*metabolism/*pharmacology ; Ligands ; Neurons/cytology/*drug effects ; Piperidines/*chemical synthesis/chemistry/metabolism/*pharmacology ; Protein Conformation ; Rats ; Tacrolimus Binding Proteins/*metabolism/pharmacology
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  • 12
    Publication Date: 2004-02-07
    Description: The 1918 "Spanish" influenza pandemic represents the largest recorded outbreak of any infectious disease. The crystal structure of the uncleaved precursor of the major surface antigen of the extinct 1918 virus was determined at 3.0 angstrom resolution after reassembly of the hemagglutinin gene from viral RNA fragments preserved in 1918 formalin-fixed lung tissues. A narrow avian-like receptor-binding site, two previously unobserved histidine patches, and a less exposed surface loop at the cleavage site that activates viral membrane fusion reveal structural features primarily found in avian viruses, which may have contributed to the extraordinarily high infectivity and mortality rates observed during 1918.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stevens, James -- Corper, Adam L -- Basler, Christopher F -- Taubenberger, Jeffery K -- Palese, Peter -- Wilson, Ian A -- AI058113/AI/NIAID NIH HHS/ -- AI42266/AI/NIAID NIH HHS/ -- AI50619/AI/NIAID NIH HHS/ -- CA55896/CA/NCI NIH HHS/ -- P50-GM 62411/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Mar 19;303(5665):1866-70. Epub 2004 Feb 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14764887" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Carbohydrate Conformation ; Cloning, Molecular ; Crystallography, X-Ray ; Glycosylation ; Hemagglutinin Glycoproteins, Influenza Virus/*chemistry/metabolism ; Histidine/chemistry/metabolism ; History, 20th Century ; Humans ; Hydrogen Bonding ; Influenza A virus/classification/*immunology/pathogenicity ; Influenza, Human/epidemiology/history/virology ; Molecular Sequence Data ; Protein Conformation ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Receptors, Virus/metabolism ; Sialic Acids/metabolism
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  • 13
    Publication Date: 2004-09-09
    Description: We describe the synthesis and properties of a small molecule mimic of Smac, a pro-apoptotic protein that functions by relieving inhibitor-of-apoptosis protein (IAP)-mediated suppression of caspase activity. The compound binds to X chromosome- encoded IAP (XIAP), cellular IAP 1 (cIAP-1), and cellular IAP 2 (cIAP-2) and synergizes with both tumor necrosis factor alpha (TNFalpha) and TNF-related apoptosis-inducing ligand (TRAIL) to potently induce caspase activation and apoptosis in human cancer cells. The molecule has allowed a temporal, unbiased evaluation of the roles that IAP proteins play during signaling from TRAIL and TNF receptors. The compound is also a lead structure for the development of IAP antagonists potentially useful as therapy for cancer and inflammatory diseases.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Lin -- Thomas, Ranny Mathew -- Suzuki, Hidetaka -- De Brabander, Jef K -- Wang, Xiaodong -- Harran, Patrick G -- P01 CA95471/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2004 Sep 3;305(5689):1471-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15353805" target="_blank"〉PubMed〈/a〉
    Keywords: Alkynes/chemical synthesis/chemistry/metabolism/*pharmacology ; *Apoptosis ; Apoptosis Regulatory Proteins ; Biotinylation ; *Carrier Proteins/chemistry/metabolism ; Caspase Inhibitors ; Caspases/metabolism ; Cell Line, Tumor ; Computer Simulation ; Dimerization ; Dipeptides/chemical synthesis/chemistry/metabolism/*pharmacology ; Diynes ; Glioblastoma ; Humans ; Inhibitor of Apoptosis Proteins ; Intracellular Signaling Peptides and Proteins ; Membrane Glycoproteins/metabolism/*pharmacology ; *Mitochondrial Proteins/chemistry/metabolism ; *Molecular Mimicry ; NF-kappa B/metabolism ; Poly(ADP-ribose) Polymerases/metabolism ; Protein Binding ; Protein Conformation ; Protein Engineering ; Proteins/metabolism ; Signal Transduction ; TNF-Related Apoptosis-Inducing Ligand ; Tetrazoles/chemical synthesis/chemistry/metabolism/*pharmacology ; Tumor Necrosis Factor-alpha/metabolism/*pharmacology ; X-Linked Inhibitor of Apoptosis Protein
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  • 14
    Publication Date: 2004-04-17
    Description: Mitochondrial dysfunction is a hallmark of beta-amyloid (Abeta)-induced neuronal toxicity in Alzheimer's disease (AD). Here, we demonstrate that Abeta-binding alcohol dehydrogenase (ABAD) is a direct molecular link from Abeta to mitochondrial toxicity. Abeta interacts with ABAD in the mitochondria of AD patients and transgenic mice. The crystal structure of Abeta-bound ABAD shows substantial deformation of the active site that prevents nicotinamide adenine dinucleotide (NAD) binding. An ABAD peptide specifically inhibits ABAD-Abeta interaction and suppresses Abeta-induced apoptosis and free-radical generation in neurons. Transgenic mice overexpressing ABAD in an Abeta-rich environment manifest exaggerated neuronal oxidative stress and impaired memory. These data suggest that the ABAD-Abeta interaction may be a therapeutic target in AD.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lustbader, Joyce W -- Cirilli, Maurizio -- Lin, Chang -- Xu, Hong Wei -- Takuma, Kazuhiro -- Wang, Ning -- Caspersen, Casper -- Chen, Xi -- Pollak, Susan -- Chaney, Michael -- Trinchese, Fabrizio -- Liu, Shumin -- Gunn-Moore, Frank -- Lue, Lih-Fen -- Walker, Douglas G -- Kuppusamy, Periannan -- Zewier, Zay L -- Arancio, Ottavio -- Stern, David -- Yan, Shirley ShiDu -- Wu, Hao -- 1K07AG00959/AG/NIA NIH HHS/ -- AG16736/AG/NIA NIH HHS/ -- AG17490/AG/NIA NIH HHS/ -- NS42855/NS/NINDS NIH HHS/ -- P50AG08702/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 2004 Apr 16;304(5669):448-52.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Reproductive Sciences and Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15087549" target="_blank"〉PubMed〈/a〉
    Keywords: 3-Hydroxyacyl CoA Dehydrogenases/chemistry/*metabolism ; Aged ; Aged, 80 and over ; Alzheimer Disease/*metabolism ; Amino Acid Sequence ; Amyloid beta-Peptides/chemistry/genetics/*metabolism ; Animals ; Binding Sites ; Brain/*metabolism ; Brain Chemistry ; Carrier Proteins/chemistry/*metabolism ; Cells, Cultured ; Cerebral Cortex/chemistry/metabolism ; Crystallization ; DNA Fragmentation ; Hippocampus/physiology ; Humans ; Learning ; Memory ; Mice ; Mice, Transgenic ; Microscopy, Confocal ; Microscopy, Immunoelectron ; Mitochondria/chemistry/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Mutation ; NAD/metabolism ; Neurons/metabolism ; Protein Binding ; Protein Conformation ; Reactive Oxygen Species/metabolism
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  • 15
    Publication Date: 2004-03-27
    Description: Images of entire cells are preceding atomic structures of the separate molecular machines that they contain. The resulting gap in knowledge can be partly bridged by protein-protein interactions, bioinformatics, and electron microscopy. Here we use interactions of known three-dimensional structure to model a large set of yeast complexes, which we also screen by electron microscopy. For 54 of 102 complexes, we obtain at least partial models of interacting subunits. For 29, including the exosome, the chaperonin containing TCP-1, a 3'-messenger RNA degradation complex, and RNA polymerase II, the process suggests atomic details not easily seen by homology, involving the combination of two or more known structures. We also consider interactions between complexes (cross-talk) and use these to construct a structure-based network of molecular machines in the cell.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Aloy, Patrick -- Bottcher, Bettina -- Ceulemans, Hugo -- Leutwein, Christina -- Mellwig, Christian -- Fischer, Susanne -- Gavin, Anne-Claude -- Bork, Peer -- Superti-Furga, Giulio -- Serrano, Luis -- Russell, Robert B -- New York, N.Y. -- Science. 2004 Mar 26;303(5666):2026-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉European Molecular Biology Laboratory, Structural and Computational Biology Programme, 1, 69117 Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15044803" target="_blank"〉PubMed〈/a〉
    Keywords: Chaperonins/chemistry/metabolism ; Computational Biology ; Image Processing, Computer-Assisted ; Microscopy, Electron ; Models, Biological ; Models, Molecular ; Nuclear Proteins/chemistry/metabolism ; Protein Binding ; Protein Conformation ; *Protein Interaction Mapping ; Protein Structure, Tertiary ; RNA Polymerase II/chemistry/metabolism ; Ribonuclease P/chemistry/metabolism ; Saccharomyces cerevisiae/chemistry/*metabolism/ultrastructure ; Saccharomyces cerevisiae Proteins/chemistry/*metabolism ; Transcription Factors/chemistry/metabolism
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  • 16
    Publication Date: 2004-02-14
    Description: The tumor suppressor p53 exerts its anti-neoplastic activity primarily through the induction of apoptosis. We found that cytosolic localization of endogenous wild-type or trans-activation-deficient p53 was necessary and sufficient for apoptosis. p53 directly activated the proapoptotic Bcl-2 protein Bax in the absence of other proteins to permeabilize mitochondria and engage the apoptotic program. p53 also released both proapoptotic multidomain proteins and BH3-only proteins [Proapoptotic Bcl-2 family proteins that share only the third Bcl-2 homology domain (BH3)] that were sequestered by Bcl-xL. The transcription-independent activation of Bax by p53 occurred with similar kinetics and concentrations to those produced by activated Bid. We propose that when p53 accumulates in the cytosol, it can function analogously to the BH3-only subset of proapoptotic Bcl-2 proteins to activate Bax and trigger apoptosis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chipuk, Jerry E -- Kuwana, Tomomi -- Bouchier-Hayes, Lisa -- Droin, Nathalie M -- Newmeyer, Donald D -- Schuler, Martin -- Green, Douglas R -- AI40646/AI/NIAID NIH HHS/ -- AI47891/AI/NIAID NIH HHS/ -- GM52735/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Feb 13;303(5660):1010-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14963330" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Apoptosis ; BH3 Interacting Domain Death Agonist Protein ; Carrier Proteins/metabolism ; Cell Line, Transformed ; Cell Nucleus/metabolism ; Cells, Cultured ; Cytochromes c/metabolism ; Cytosol/metabolism ; Gene Expression Regulation ; Genes, p53 ; HeLa Cells ; Humans ; Intracellular Membranes/*physiology ; Liposomes/metabolism ; Mice ; Mitochondria/*physiology ; Mutation ; Permeability ; Protein Conformation ; Proto-Oncogene Proteins/chemistry/genetics/*metabolism ; Proto-Oncogene Proteins c-bcl-2/metabolism ; Recombinant Fusion Proteins/metabolism ; Tumor Suppressor Protein p53/chemistry/*metabolism ; Ultraviolet Rays ; Wheat Germ Agglutinins/pharmacology ; bcl-2-Associated X Protein ; bcl-X Protein
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  • 17
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-03-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rutherford, A W -- Boussac, A -- New York, N.Y. -- Science. 2004 Mar 19;303(5665):1782-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Service of Bioenergetics, CNRS URA 2096, Departement de Biologie Joliot Curie, CEA Saclay, 91191 Gif-sur-Yvette, France. rutherford@dsvidf.cea.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15031485" target="_blank"〉PubMed〈/a〉
    Keywords: Calcium/analysis/metabolism ; Catalytic Domain ; Crystallography, X-Ray ; Electrons ; Free Radicals ; Histidine/chemistry/metabolism ; Hydrogen Bonding ; Ligands ; Manganese/analysis/metabolism ; Models, Chemical ; Models, Molecular ; Oxidation-Reduction ; Oxygen/analysis/metabolism ; Photolysis ; Photosynthetic Reaction Center Complex Proteins/chemistry/metabolism ; Photosystem II Protein Complex/*chemistry/*metabolism ; Protein Conformation ; Protein Structure, Quaternary ; Protons ; Tyrosine/*analogs & derivatives/chemistry/metabolism ; Water/*metabolism
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  • 18
    Publication Date: 2004-09-14
    Description: The first structure of an ammonia channel from the Amt/MEP/Rh protein superfamily, determined to 1.35 angstrom resolution, shows it to be a channel that spans the membrane 11 times. Two structurally similar halves span the membrane with opposite polarity. Structures with and without ammonia or methyl ammonia show a vestibule that recruits NH4+/NH3, a binding site for NH4+, and a 20 angstrom-long hydrophobic channel that lowers the NH4+ pKa to below 6 and conducts NH3. Favorable interactions for NH3 are seen within the channel and use conserved histidines. Reconstitution of AmtB into vesicles shows that AmtB conducts uncharged NH3.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Khademi, Shahram -- O'Connell, Joseph 3rd -- Remis, Jonathan -- Robles-Colmenares, Yaneth -- Miercke, Larry J W -- Stroud, Robert M -- GM24485/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Sep 10;305(5690):1587-94.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Biophysics, S412C Genentech Hall, University of California-San Francisco, 600 16th Street, San Francisco, CA 94143-2240, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15361618" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Ammonia/*metabolism ; Binding Sites ; Biological Transport ; Cation Transport Proteins/*chemistry/genetics/metabolism ; Cell Membrane/chemistry ; Crystallization ; Crystallography, X-Ray ; Escherichia coli/*chemistry/metabolism ; Escherichia coli Proteins/*chemistry/genetics/metabolism ; Hydrogen Bonding ; Hydrogen-Ion Concentration ; Hydrophobic and Hydrophilic Interactions ; Liposomes ; Membrane Potentials ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Folding ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Quaternary Ammonium Compounds/metabolism ; Rh-Hr Blood-Group System/chemistry/metabolism ; Sequence Alignment ; Water/chemistry/metabolism
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  • 19
    Publication Date: 2004-03-16
    Description: We used force-clamp atomic force microscopy to measure the end-to-end length of the small protein ubiquitin during its folding reaction at the single-molecule level. Ubiquitin was first unfolded and extended at a high force, then the stretching force was quenched and protein folding was observed. The folding trajectories were continuous and marked by several distinct stages. The time taken to fold was dependent on the contour length of the unfolded protein and the stretching force applied during folding. The folding collapse was marked by large fluctuations in the end-to-end length of the protein, but these fluctuations vanished upon the final folding contraction. These direct observations of the complete folding trajectory of a protein provide a benchmark to determine the physical basis of the folding reaction.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fernandez, Julio M -- Li, Hongbin -- New York, N.Y. -- Science. 2004 Mar 12;303(5664):1674-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Columbia University, New York, NY 10027, USA. jfernandez@columbia.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15017000" target="_blank"〉PubMed〈/a〉
    Keywords: Chemistry, Physical ; *Microscopy, Atomic Force ; Physicochemical Phenomena ; Polyubiquitin/*chemistry ; Protein Conformation ; Protein Denaturation ; *Protein Folding ; Protein Structure, Secondary ; Time Factors ; Ubiquitin/*chemistry
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  • 20
    Publication Date: 2004-01-06
    Description: The crystal structure of biotin synthase from Escherichia coli in complex with S-adenosyl-L-methionine and dethiobiotin has been determined to 3.4 angstrom resolution. This structure addresses how "AdoMet radical" or "radical SAM" enzymes use Fe4S4 clusters and S-adenosyl-L-methionine to generate organic radicals. Biotin synthase catalyzes the radical-mediated insertion of sulfur into dethiobiotin to form biotin. The structure places the substrates between the Fe4S4 cluster, essential for radical generation, and the Fe2S2 cluster, postulated to be the source of sulfur, with both clusters in unprecedented coordination environments.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1456065/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1456065/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Berkovitch, Frederick -- Nicolet, Yvain -- Wan, Jason T -- Jarrett, Joseph T -- Drennan, Catherine L -- NSLS X25/NS/NINDS NIH HHS/ -- R01 GM059175/GM/NIGMS NIH HHS/ -- R01-GM59175/GM/NIGMS NIH HHS/ -- R01-GM65337/GM/NIGMS NIH HHS/ -- T32-GM07229/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jan 2;303(5654):76-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14704425" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Binding Sites ; Biotin/*analogs & derivatives/*chemistry/metabolism ; Catalysis ; Crystallization ; Crystallography, X-Ray ; Dimerization ; Escherichia coli/*enzymology ; Escherichia coli Proteins/*chemistry/*metabolism ; Hydrogen/chemistry ; Hydrogen Bonding ; Iron/chemistry ; Ligands ; Models, Molecular ; Protein Binding ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; S-Adenosylmethionine/*chemistry/metabolism ; Sulfur/chemistry ; Sulfurtransferases/*chemistry/*metabolism
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  • 21
    Publication Date: 2004-01-13
    Description: Advances in transition state theory and computer simulations are providing new insights into the sources of enzyme catalysis. Both lowering of the activation free energy and changes in the generalized transmission coefficient (recrossing of the transition state, tunneling, and nonequilibrium contributions) can play a role. A framework for understanding these effects is presented, and the contributions of the different factors, as illustrated by specific enzymes, are identified and quantified by computer simulations. The resulting understanding of enzyme catalysis is used to comment on alternative proposals of how enzymes work.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Garcia-Viloca, Mireia -- Gao, Jiali -- Karplus, Martin -- Truhlar, Donald G -- New York, N.Y. -- Science. 2004 Jan 9;303(5655):186-95.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14716003" target="_blank"〉PubMed〈/a〉
    Keywords: *Catalysis ; Computer Simulation ; Enzymes/*chemistry/*metabolism ; Kinetics ; Mathematics ; Models, Chemical ; Models, Molecular ; Protein Conformation ; Thermodynamics
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  • 22
    Publication Date: 2004-10-02
    Description: Microbial sensory rhodopsins are a family of membrane-embedded photoreceptors in prokaryotic and eukaryotic organisms. Structures of archaeal rhodopsins, which function as light-driven ion pumps or photosensors, have been reported. We present the structure of a eubacterial rhodopsin, which differs from those of previously characterized archaeal rhodopsins in its chromophore and cytoplasmic-side portions. Anabaena sensory rhodopsin exhibits light-induced interconversion between stable 13-cis and all-trans states of the retinylidene protein. The ratio of its cis and trans chromophore forms depends on the wavelength of illumination, thus providing a mechanism for a single protein to signal the color of light, for example, to regulate color-sensitive processes such as chromatic adaptation in photosynthesis. Its cytoplasmic half channel, highly hydrophobic in the archaeal rhodopsins, contains numerous hydrophilic residues networked by water molecules, providing a connection from the photoactive site to the cytoplasmic surface believed to interact with the receptor's soluble 14-kilodalton transducer.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vogeley, Lutz -- Sineshchekov, Oleg A -- Trivedi, Vishwa D -- Sasaki, Jun -- Spudich, John L -- Luecke, Hartmut -- R01-GM067808/GM/NIGMS NIH HHS/ -- R01-GM59970/GM/NIGMS NIH HHS/ -- R37-GM27750/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Nov 19;306(5700):1390-3. Epub 2004 Sep 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15459346" target="_blank"〉PubMed〈/a〉
    Keywords: Anabaena/*chemistry ; Archaeal Proteins/chemistry ; Bacterial Proteins/chemistry ; Binding Sites ; Chemistry, Physical ; Crystallography, X-Ray ; Cytoplasm/chemistry ; Hydrogen Bonding ; Light ; Lipid Bilayers/chemistry ; Models, Molecular ; Physicochemical Phenomena ; Protein Conformation ; Protein Structure, Secondary ; Sensory Rhodopsins/*chemistry ; Water
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  • 23
    facet.materialart.
    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-07-17
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉von Hippel, Peter H -- GM-15792/GM/NIGMS NIH HHS/ -- GM-29158/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jul 16;305(5682):350-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Biology and Department of Chemistry, University of Oregon, Eugene, OR 97403, USA. petevh@molbio.uoregon.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15256661" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/*metabolism ; Binding Sites ; DNA, Bacterial/*chemistry/*metabolism ; Diffusion ; Dimerization ; Escherichia coli/chemistry/genetics/metabolism ; Escherichia coli Proteins/chemistry/metabolism ; *Gene Expression Regulation, Bacterial ; Hydrogen Bonding ; Kinetics ; Lac Operon ; Lac Repressors ; Models, Genetic ; Models, Molecular ; Nucleic Acid Conformation ; Operator Regions, Genetic ; Protein Binding ; Protein Conformation ; Protein Structure, Tertiary ; Repressor Proteins/*chemistry/*metabolism ; Static Electricity ; Thermodynamics ; *Transcription, Genetic
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  • 24
    Publication Date: 2004-01-24
    Description: DsbA, a thioredoxin superfamily member, introduces disulfide bonds into newly translocated proteins. This process is thought to occur via formation of mixed disulfide complexes between DsbA and its substrates. However, these complexes are difficult to detect, probably because of their short-lived nature. Here we show that it is possible to detect such covalent intermediates in vivo by a mutation in DsbA that alters cis proline-151. Further, this mutant allowed us to identify substrates of DsbA. Alteration of the cis proline, highly conserved among thioredoxin superfamily members, may be useful for the detection of substrates and intermediate complexes in other systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kadokura, Hiroshi -- Tian, Hongping -- Zander, Thomas -- Bardwell, James C A -- Beckwith, Jon -- GM41883/GM/NIGMS NIH HHS/ -- GM57039/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jan 23;303(5657):534-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14739460" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Bacterial Proteins/chemistry/metabolism ; Disulfides/chemistry ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli Proteins/*chemistry/*metabolism ; Isomerism ; Mass Spectrometry ; Membrane Proteins/chemistry/metabolism ; Molecular Weight ; Mutation ; Oxidation-Reduction ; Plasmids ; Proline/chemistry ; Protein Conformation ; Protein Disulfide-Isomerases/*chemistry/genetics/*metabolism ; *Protein Folding ; Thioredoxins/chemistry/metabolism ; Transduction, Genetic
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  • 25
    Publication Date: 2004-11-13
    Description: Variant Creutzfeldt-Jakob disease (vCJD) is a unique and highly distinctive clinicopathological and molecular phenotype of human prion disease associated with infection with bovine spongiform encephalopathy (BSE)-like prions. Here, we found that generation of this phenotype in transgenic mice required expression of human prion protein (PrP) with methionine 129. Expression of human PrP with valine 129 resulted in a distinct phenotype and, remarkably, persistence of a barrier to transmission of BSE-derived prions on subpassage. Polymorphic residue 129 of human PrP dictated propagation of distinct prion strains after BSE prion infection. Thus, primary and secondary human infection with BSE-derived prions may result in sporadic CJD-like or novel phenotypes in addition to vCJD, depending on the genotype of the prion source and the recipient.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wadsworth, Jonathan D F -- Asante, Emmanuel A -- Desbruslais, Melanie -- Linehan, Jacqueline M -- Joiner, Susan -- Gowland, Ian -- Welch, Julie -- Stone, Lisa -- Lloyd, Sarah E -- Hill, Andrew F -- Brandner, Sebastian -- Collinge, John -- New York, N.Y. -- Science. 2004 Dec 3;306(5702):1793-6. Epub 2004 Nov 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15539564" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid/genetics ; Animals ; Brain/pathology ; Cattle ; Creutzfeldt-Jakob Syndrome/genetics/*metabolism/*pathology/transmission ; Encephalopathy, Bovine Spongiform/pathology/transmission ; Humans ; Methionine ; Mice ; Mice, Transgenic ; Phenotype ; Polymorphism, Genetic ; PrPC Proteins/chemistry/*genetics/metabolism ; PrPSc Proteins/metabolism/*pathogenicity ; Prions ; Protein Conformation ; Protein Precursors/genetics ; *Valine
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  • 26
    Publication Date: 2004-06-12
    Description: A tight coupling between adenosine triphosphate (ATP) hydrolysis and vectorial ion transport has to be maintained by ATP-consuming ion pumps. We report two crystal structures of Ca2+-bound sarco(endo)plasmic reticulum Ca2+-adenosine triphosphatase (SERCA) at 2.6 and 2.9 angstrom resolution in complex with (i) a nonhydrolyzable ATP analog [adenosine (beta-gamma methylene)-triphosphate] and (ii) adenosine diphosphate plus aluminum fluoride. SERCA reacts with ATP by an associative mechanism mediated by two Mg2+ ions to form an aspartyl-phosphorylated intermediate state (Ca2-E1 approximately P). The conformational changes that accompany the reaction with ATP pull the transmembrane helices 1 and 2 and close a cytosolic entrance for Ca2+, thereby preventing backflow before Ca2+ is released on the other side of the membrane.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sorensen, Thomas Lykke-Moller -- Moller, Jesper Vuust -- Nissen, Poul -- New York, N.Y. -- Science. 2004 Jun 11;304(5677):1672-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15192230" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate/metabolism ; Adenosine Triphosphate/*analogs & derivatives/*metabolism ; Aluminum Compounds/metabolism ; Animals ; Binding Sites ; Calcium/*metabolism ; Calcium-Transporting ATPases/*chemistry/*metabolism ; Crystallization ; Crystallography, X-Ray ; Cytosol/metabolism ; Fluorides/metabolism ; Models, Molecular ; Muscle Fibers, Fast-Twitch/*enzymology ; Phosphorylation ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Rabbits ; Sarcoplasmic Reticulum Calcium-Transporting ATPases
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  • 27
    Publication Date: 2004-05-08
    Description: Copper active sites play a major role in enzymatic activation of dioxygen. We trapped the copper-dioxygen complex in the enzyme peptidylglycine-alphahydroxylating monooxygenase (PHM) by freezing protein crystals that had been soaked with a slow substrate and ascorbate in the presence of oxygen. The x-ray crystal structure of this precatalytic complex, determined to 1.85-angstrom resolution, shows that oxygen binds to one of the coppers in the enzyme with an end-on geometry. Given this structure, it is likely that dioxygen is directly involved in the electron transfer and hydrogen abstraction steps of the PHM reaction. These insights may apply to other copper oxygen-activating enzymes, such as dopamine beta-monooxygenase, and to the design of biomimetic complexes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Prigge, Sean T -- Eipper, Betty A -- Mains, Richard E -- Amzel, L Mario -- DK32949/DK/NIDDK NIH HHS/ -- New York, N.Y. -- Science. 2004 May 7;304(5672):864-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology and Molecular Immunology, The Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15131304" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding Sites ; Catalysis ; Catalytic Domain ; Copper/*metabolism ; Crystallization ; Crystallography, X-Ray ; Dipeptides/chemistry/metabolism ; Electron Transport ; Glycine/chemistry/metabolism ; Hydrogen/metabolism ; Hydrogen Bonding ; Ligands ; Mixed Function Oxygenases/*chemistry/*metabolism ; Models, Molecular ; Multienzyme Complexes/*chemistry/*metabolism ; Oxidation-Reduction ; Oxygen/*metabolism ; Peptides/metabolism ; Protein Conformation ; Rats ; Water/metabolism
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  • 28
    Publication Date: 2004-08-03
    Description: Recombinant mouse prion protein (recMoPrP) produced in Escherichia coli was polymerized into amyloid fibrils that represent a subset of beta sheet-rich structures. Fibrils consisting of recMoPrP(89-230) were inoculated intracerebrally into transgenic (Tg) mice expressing MoPrP(89-231). The mice developed neurologic dysfunction between 380 and 660 days after inoculation. Brain extracts showed protease-resistant PrP by Western blotting; these extracts transmitted disease to wild-type FVB mice and Tg mice overexpressing PrP, with incubation times of 150 and 90 days, respectively. Neuropathological findings suggest that a novel prion strain was created. Our results provide compelling evidence that prions are infectious proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Legname, Giuseppe -- Baskakov, Ilia V -- Nguyen, Hoang-Oanh B -- Riesner, Detlev -- Cohen, Fred E -- DeArmond, Stephen J -- Prusiner, Stanley B -- AG02132/AG/NIA NIH HHS/ -- AG021601/AG/NIA NIH HHS/ -- AG10770/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 2004 Jul 30;305(5684):673-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Neurodegenerative Diseases, University of California, San Francisco, CA 94143, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15286374" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid/chemistry/metabolism ; Animals ; Biopolymers ; Brain/metabolism/pathology ; Brain Chemistry ; Escherichia coli/genetics ; Female ; Glycosylation ; Male ; Mice ; Mice, Transgenic ; Plaque, Amyloid/pathology ; PrPSc Proteins/analysis/metabolism ; Prion Diseases/*etiology/pathology/transmission ; Prions/administration & dosage/biosynthesis/chemistry/*pathogenicity ; Protein Conformation ; Protein Folding ; Recombinant Proteins/administration & dosage/biosynthesis/chemistry ; Time Factors ; Tissue Extracts/administration & dosage ; Vacuoles/pathology
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  • 29
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-06-26
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sterner, Reinhard -- Schmid, Franz X -- New York, N.Y. -- Science. 2004 Jun 25;304(5679):1916-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universitat Regensburg, Institut fur Biophysik und Physikalische Biochemie, D-93040 Regensburg, Germany. reinhard.sterner@biologie.uni-regensburg.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15218133" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Amino Acid Substitution ; Binding Sites ; Catalysis ; Computational Biology ; Computer Simulation ; Directed Molecular Evolution ; *Escherichia coli Proteins/chemistry/genetics/metabolism ; Glutamic Acid/chemistry ; Glyceraldehyde 3-Phosphate/metabolism ; Histidine/chemistry ; Hydrogen Bonding ; Lysine/chemistry ; Models, Molecular ; *Periplasmic Binding Proteins/chemistry/genetics/metabolism ; Protein Conformation ; *Protein Engineering ; *Triose-Phosphate Isomerase/chemistry/metabolism
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  • 30
    Publication Date: 2004-02-14
    Description: The structure of the general transcription factor IIB (TFIIB) in a complex with RNA polymerase II reveals three features crucial for transcription initiation: an N-terminal zinc ribbon domain of TFIIB that contacts the "dock" domain of the polymerase, near the path of RNA exit from a transcribing enzyme; a "finger" domain of TFIIB that is inserted into the polymerase active center; and a C-terminal domain, whose interaction with both the polymerase and with a TATA box-binding protein (TBP)-promoter DNA complex orients the DNA for unwinding and transcription. TFIIB stabilizes an early initiation complex, containing an incomplete RNA-DNA hybrid region. It may interact with the template strand, which sets the location of the transcription start site, and may interfere with RNA exit, which leads to abortive initiation or promoter escape. The trajectory of promoter DNA determined by the C-terminal domain of TFIIB traverses sites of interaction with TFIIE, TFIIF, and TFIIH, serving to define their roles in the transcription initiation process.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bushnell, David A -- Westover, Kenneth D -- Davis, Ralph E -- Kornberg, Roger D -- AI21144/AI/NIAID NIH HHS/ -- GM49985/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Feb 13;303(5660):983-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14963322" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Binding Sites ; Crystallization ; Crystallography, X-Ray ; DNA/chemistry/metabolism ; Models, Molecular ; Molecular Sequence Data ; Nuclear Magnetic Resonance, Biomolecular ; Nucleic Acid Hybridization ; Promoter Regions, Genetic ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; RNA/chemistry/metabolism ; RNA Polymerase II/*chemistry/metabolism ; Saccharomyces cerevisiae Proteins/chemistry/metabolism ; TATA Box ; TATA-Box Binding Protein/chemistry/metabolism ; Templates, Genetic ; Transcription Factor TFIIB/*chemistry/metabolism ; Transcription Factors, TFII/chemistry/metabolism ; *Transcription, Genetic ; Zinc/chemistry
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  • 31
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-01-17
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dobberstein, Bernhard -- Sinning, Irmgard -- New York, N.Y. -- Science. 2004 Jan 16;303(5656):320-2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Zentrum fur Molekulare Biologie and I. Sinning is at the Biochemiezentrum, Universitat Heidelberg, 69120 Heidelberg, Germany. dobberstein@zmbh.uni-heidelberg.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14726579" target="_blank"〉PubMed〈/a〉
    Keywords: Archaeal Proteins/*chemistry/metabolism ; Cell Membrane/chemistry/metabolism ; Crystallography, X-Ray ; Lipid Bilayers ; Membrane Proteins/*chemistry/metabolism ; Methanococcus/*chemistry/metabolism ; Models, Molecular ; Peptides/metabolism ; Protein Binding ; Protein Conformation ; Protein Structure, Secondary ; Protein Subunits ; *Protein Transport
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  • 32
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-12-04
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Carrell, Robin W -- New York, N.Y. -- Science. 2004 Dec 3;306(5702):1692-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 2XY, UK. rwc1000@cam.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15576598" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Appendix/chemistry ; Brain/pathology ; Carrier State ; Cattle ; Creutzfeldt-Jakob Syndrome/epidemiology/genetics/*metabolism/pathology ; Disease Outbreaks ; Encephalopathy, Bovine Spongiform/epidemiology/metabolism ; Genetic Predisposition to Disease ; Genotype ; Great Britain/epidemiology ; Humans ; Methionine ; Mice ; Mice, Transgenic ; Polymorphism, Genetic ; PrPC Proteins/analysis/chemistry/*genetics/pathogenicity ; Protein Conformation ; Valine
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  • 33
    Publication Date: 2004-06-05
    Description: Condensins are conserved proteins containing SMC (structural maintenance of chromosomes) moieties that organize and compact chromosomes in an unknown mechanism essential for faithful chromosome partitioning. We show that MukBEF, the condensin in Escherichia coli, cooperatively compacts a single DNA molecule into a filament with an ordered, repetitive structure in an adenosine triphosphate (ATP) binding-dependent manner. When stretched to a tension of approximately 17 piconewtons, the filament extended in a series of repetitive transitions in a broad distribution centered on 45 nanometers. A filament so extended and held at a lower force recondensed in steps of 35 nanometers or its multiples; this cycle was repeatable even in the absence of ATP and free MukBEF. Remarkably, the pattern of transitions displayed by a given filament during the initial extension was identical in every subsequent extension. Hence, after being deformed micrometers in length, each filament returned to its original compact structure without the addition of energy. Incubation with topoisomerase I increased the rate of recondensation and allowed the structure to extend and reform almost reversibly, indicating that supercoiled DNA is trapped in the condensed structure. We suggest a new model for how MukBEF organizes the bacterial chromosome in vivo.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Case, Ryan B -- Chang, Yun-Pei -- Smith, Steven B -- Gore, Jeff -- Cozzarelli, Nicholas R -- Bustamante, Carlos -- GM31655/GM/NIGMS NIH HHS/ -- GM32543/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jul 9;305(5681):222-7. Epub 2004 Jun 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15178751" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Binding Sites ; Chemistry, Physical ; Chromosomal Proteins, Non-Histone/chemistry/*metabolism ; DNA Topoisomerases, Type I/metabolism ; DNA, Bacterial/*chemistry/*metabolism ; DNA, Superhelical/chemistry/metabolism ; Dimerization ; Escherichia coli/genetics ; Escherichia coli Proteins/chemistry/*metabolism ; Lasers ; Microspheres ; Models, Chemical ; Models, Molecular ; *Nucleic Acid Conformation ; Physicochemical Phenomena ; Protein Binding ; Protein Conformation ; Protein Subunits ; Repressor Proteins/chemistry/*metabolism
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  • 34
    Publication Date: 2004-08-03
    Description: The motor protein kinesin moves along microtubules, driven by adenosine triphosphate (ATP) hydrolysis. However, it remains unclear how kinesin converts the chemical energy into mechanical movement. We report crystal structures of monomeric kinesin KIF1A with three transition-state analogs: adenylyl imidodiphosphate (AMP-PNP), adenosine diphosphate (ADP)-vanadate, and ADP-AlFx (aluminofluoride complexes). These structures, together with known structures of the ADP-bound state and the adenylyl-(beta,gamma-methylene) diphosphate (AMP-PCP)-bound state, show that kinesin uses two microtubule-binding loops in an alternating manner to change its interaction with microtubules during the ATP hydrolysis cycle; loop L11 is extended in the AMP-PNP structure, whereas loop L12 is extended in the ADP structure. ADP-vanadate displays an intermediate structure in which a conformational change in two switch regions causes both loops to be raised from the microtubule, thus actively detaching kinesin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nitta, Ryo -- Kikkawa, Masahide -- Okada, Yasushi -- Hirokawa, Nobutaka -- New York, N.Y. -- Science. 2004 Jul 30;305(5684):678-83.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology and Anatomy, University of Tokyo, Graduate School of Medicine, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15286375" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Adenylyl Imidodiphosphate/metabolism ; Aluminum/metabolism ; Animals ; Binding Sites ; Crystallography, X-Ray ; Fluorides/metabolism ; Hydrogen Bonding ; Kinesin/*chemistry/*metabolism ; Mice ; Microtubules/*metabolism ; Models, Molecular ; Nerve Tissue Proteins/*chemistry/*metabolism ; Phosphates/metabolism ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Vanadates/metabolism
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  • 35
    Publication Date: 2004-06-26
    Description: Rational design of enzymes is a stringent test of our understanding of protein chemistry and has numerous potential applications. Here, we present and experimentally validate the computational design of enzyme activity in proteins of known structure. We have predicted mutations that introduce triose phosphate isomerase activity into ribose-binding protein, a receptor that normally lacks enzyme activity. The resulting designs contain 18 to 22 mutations, exhibit 10(5)- to 10(6)-fold rate enhancements over the uncatalyzed reaction, and are biologically active, in that they support the growth of Escherichia coli under gluconeogenic conditions. The inherent generality of the design method suggests that many enzymes can be designed by this approach.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dwyer, Mary A -- Looger, Loren L -- Hellinga, Homme W -- New York, N.Y. -- Science. 2004 Jun 25;304(5679):1967-71.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15218149" target="_blank"〉PubMed〈/a〉
    Keywords: Algorithms ; Binding Sites ; Catalysis ; Catalytic Domain ; Computational Biology ; Computer Simulation ; Dihydroxyacetone Phosphate/metabolism ; Dimerization ; Directed Molecular Evolution ; Enzyme Stability ; Escherichia coli/genetics/growth & development/metabolism ; *Escherichia coli Proteins/chemistry/genetics/metabolism ; Glyceraldehyde 3-Phosphate/metabolism ; Glycerol/metabolism ; Hydrogen Bonding ; Kinetics ; Lactates/metabolism ; Ligands ; Models, Molecular ; Molecular Conformation ; Mutation ; *Periplasmic Binding Proteins/chemistry/genetics/metabolism ; Protein Conformation ; *Protein Engineering ; Protons ; *Triose-Phosphate Isomerase/chemistry/metabolism
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  • 36
    Publication Date: 2004-02-28
    Description: We determined the minimal portion of Escherichia coli RNA polymerase (RNAP) holoenzyme able to accomplish promoter melting, the crucial step in transcription initiation that provides RNAP access to the template strand. Upon duplex DNA binding, the N terminus of the beta' subunit (amino acids 1 to 314) and amino acids 94 to 507 of the sigma subunit, together comprising less than one-fifth of RNAP holoenzyme, were able to melt an extended -10 promoter in a reaction remarkably similar to that of authentic holoenzyme. Our results support the model that capture of nontemplate bases extruded from the DNA helix underlies the melting process.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Young, Brian A -- Gruber, Tanja M -- Gross, Carol A -- GM 57755/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Feb 27;303(5662):1382-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departments of Stomatology and Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14988563" target="_blank"〉PubMed〈/a〉
    Keywords: DNA, Bacterial/chemistry/genetics/*metabolism ; DNA, Superhelical/chemistry/genetics/metabolism ; DNA-Directed RNA Polymerases/chemistry/*metabolism ; Escherichia coli/*enzymology/*genetics ; Holoenzymes/chemistry/metabolism ; Models, Molecular ; Nucleic Acid Conformation ; *Promoter Regions, Genetic ; Protein Conformation ; Protein Structure, Tertiary ; Sigma Factor/chemistry/*metabolism ; Templates, Genetic ; Transcription, Genetic ; Zinc Fingers
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  • 37
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-03-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hilgemann, Donald W -- New York, N.Y. -- Science. 2004 Apr 9;304(5668):223-4. Epub 2004 Mar 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, University of Texas Southwestern, Dallas, TX 75235, USA. donald.hilgemann@utsouthwestern.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15031439" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding Sites ; Cell Membrane/metabolism ; Cytoplasm/metabolism ; Eicosanoic Acids/*metabolism/pharmacology ; Hydrophobic and Hydrophilic Interactions ; Lipid Bilayers ; Membrane Lipids/*metabolism ; Micelles ; Models, Biological ; Phosphatidylinositol 4,5-Diphosphate/*metabolism/pharmacology ; Potassium Channels, Voltage-Gated/*chemistry/*metabolism ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Signal Transduction ; Sodium-Calcium Exchanger/metabolism
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  • 38
    Publication Date: 2004-09-14
    Description: We performed molecular dynamics simulations of the collapse of a two-domain protein, the BphC enzyme, into a globular structure to examine how water molecules mediate hydrophobic collapse of proteins. In the interdomain region, liquid water persists with a density 10 to 15% lower than in the bulk, even at small domain separations. Water depletion and hydrophobic collapse occur on a nanosecond time scale, which is two orders of magnitude slower than that found in the collapse of idealized paraffin-like plates. When the electrostatic protein-water forces are turned off, a dewetting transition occurs in the interdomain region and the collapse speeds up by more than an order of magnitude. When attractive van der Waals forces are turned off as well, the dewetting in the interdomain region is more profound, and the collapse is even faster.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhou, Ruhong -- Huang, Xuhui -- Margulis, Claudio J -- Berne, Bruce J -- GM4330/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Sep 10;305(5690):1605-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Computational Biology Center, IBM Thomas J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA. ruhongz@us.ibm.com〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15361621" target="_blank"〉PubMed〈/a〉
    Keywords: Computer Simulation ; *Dioxygenases ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Models, Molecular ; Oxygenases/*chemistry ; Protein Conformation ; *Protein Folding ; *Protein Structure, Tertiary ; Static Electricity ; Surface Properties ; Water/*chemistry
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  • 39
    Publication Date: 2004-02-21
    Description: Mycobacteria have low-permeability outer membranes that render them resistant to most antibiotics. Hydrophilic nutrients can enter by way of transmembrane-channel proteins called porins. An x-ray analysis of the main porin from Mycobacterium smegmatis, MspA, revealed a homooctameric goblet-like conformation with a single central channel. This is the first structure of a mycobacterial outer-membrane protein. No structure-related protein was found in the Protein Data Bank. MspA contains two consecutive beta barrels with nonpolar outer surfaces that form a ribbon around the porin, which is too narrow to fit the thickness of the mycobacterial outer membrane in contemporary models.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Faller, Michael -- Niederweis, Michael -- Schulz, Georg E -- New York, N.Y. -- Science. 2004 Feb 20;303(5661):1189-92.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Organische Chemie und Biochemie, Albert-Ludwigs-Universitat, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14976314" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Arginine/chemistry ; Cell Membrane Permeability ; Cloning, Molecular ; Crystallization ; Crystallography, X-Ray ; Electric Conductivity ; Escherichia coli/genetics ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Molecular Sequence Data ; Mutation ; Mycobacterium smegmatis/*chemistry/metabolism ; Porins/*chemistry/genetics/metabolism ; Protein Conformation ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Recombinant Proteins/chemistry
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  • 40
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-03-20
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Holmes, Edward C -- New York, N.Y. -- Science. 2004 Mar 19;303(5665):1787-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Zoology, University of Oxford, Oxford OX1 3PS, UK. edward.holmes@zoo.ox.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15031487" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Binding Sites ; Birds ; Carbohydrate Conformation ; Crystallography, X-Ray ; Disease Outbreaks/history ; Hemagglutinin Glycoproteins, Influenza Virus/*chemistry/*metabolism ; History, 20th Century ; Humans ; Influenza A virus/*immunology/metabolism/pathogenicity ; Influenza, Human/epidemiology/*history/*virology ; Membrane Glycoproteins/chemistry/metabolism ; Protein Conformation ; RNA, Viral/chemistry/genetics/isolation & purification ; Receptors, Virus/chemistry/metabolism ; Sialic Acids/metabolism ; Virulence
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  • 41
    Publication Date: 2004-05-01
    Description: Receptor tyrosine kinase genes were sequenced in non-small cell lung cancer (NSCLC) and matched normal tissue. Somatic mutations of the epidermal growth factor receptor gene EGFR were found in 15of 58 unselected tumors from Japan and 1 of 61 from the United States. Treatment with the EGFR kinase inhibitor gefitinib (Iressa) causes tumor regression in some patients with NSCLC, more frequently in Japan. EGFR mutations were found in additional lung cancer samples from U.S. patients who responded to gefitinib therapy and in a lung adenocarcinoma cell line that was hypersensitive to growth inhibition by gefitinib, but not in gefitinib-insensitive tumors or cell lines. These results suggest that EGFR mutations may predict sensitivity to gefitinib.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Paez, J Guillermo -- Janne, Pasi A -- Lee, Jeffrey C -- Tracy, Sean -- Greulich, Heidi -- Gabriel, Stacey -- Herman, Paula -- Kaye, Frederic J -- Lindeman, Neal -- Boggon, Titus J -- Naoki, Katsuhiko -- Sasaki, Hidefumi -- Fujii, Yoshitaka -- Eck, Michael J -- Sellers, William R -- Johnson, Bruce E -- Meyerson, Matthew -- New York, N.Y. -- Science. 2004 Jun 4;304(5676):1497-500. Epub 2004 Apr 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departments of Medical Oncology and Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15118125" target="_blank"〉PubMed〈/a〉
    Keywords: Adenocarcinoma/drug therapy/genetics/metabolism ; Amino Acid Motifs ; Amino Acid Sequence ; Amino Acid Substitution ; Antineoplastic Agents/pharmacology/therapeutic use ; Carcinoma, Non-Small-Cell Lung/drug therapy/*genetics/metabolism ; Cell Line, Tumor ; Controlled Clinical Trials as Topic ; Enzyme Inhibitors/pharmacology/therapeutic use ; Female ; *Genes, erbB-1 ; Humans ; Japan ; Lung Neoplasms/drug therapy/*genetics/metabolism ; Male ; Molecular Sequence Data ; *Mutation ; Mutation, Missense ; Phosphorylation ; Protein Conformation ; Protein Structure, Tertiary ; Quinazolines/pharmacology/*therapeutic use ; Receptor, Epidermal Growth Factor/*antagonists & ; inhibitors/chemistry/genetics/metabolism ; Sequence Deletion ; Treatment Outcome ; United States
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  • 42
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-09-14
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Knepper, Mark A -- Agre, Peter -- Z01 HL001285-21/Intramural NIH HHS/ -- Z99 HL999999/Intramural NIH HHS/ -- New York, N.Y. -- Science. 2004 Sep 10;305(5690):1573-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Kidney and Electrolyte Metabolism, National Institutes of Health, Bethesda, MD 20892, USA. pagre@jhmi.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15361612" target="_blank"〉PubMed〈/a〉
    Keywords: Ammonia/*metabolism ; Biological Transport ; Carrier Proteins/metabolism ; Cation Transport Proteins/*chemistry/genetics/metabolism ; Cell Membrane/metabolism ; Crystallography, X-Ray ; Escherichia coli/*chemistry/genetics/metabolism ; Escherichia coli Proteins/*chemistry/genetics/metabolism ; Glycoproteins/metabolism ; Humans ; Hydrogen-Ion Concentration ; Kidney Tubules, Collecting/metabolism ; Lipid Bilayers/metabolism ; Liver/metabolism ; Membrane Glycoproteins/metabolism ; *Membrane Transport Proteins ; Models, Molecular ; Protein Conformation ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Quaternary Ammonium Compounds/metabolism ; Rh-Hr Blood-Group System/metabolism
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  • 43
    Publication Date: 2004-01-17
    Description: Two structurally homologous guanosine triphosphatase (GTPase) domains interact directly during signal recognition particle (SRP)-mediated cotranslational targeting of proteins to the membrane. The 2.05 angstrom structure of a complex of the NG GTPase domains of Ffh and FtsY reveals a remarkably symmetric heterodimer sequestering a composite active site that contains two bound nucleotides. The structure explains the coordinate activation of the two GTPases. Conformational changes coupled to formation of their extensive interface may function allosterically to signal formation of the targeting complex to the signal-sequence binding site and the translocon. We propose that the complex represents a molecular "latch" and that its disengagement is regulated by completion of assembly of the GTPase active site.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3546161/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3546161/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Focia, Pamela J -- Shepotinovskaya, Irina V -- Seidler, James A -- Freymann, Douglas M -- GM58500/GM/NIGMS NIH HHS/ -- R01 GM058500/GM/NIGMS NIH HHS/ -- RR07707/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2004 Jan 16;303(5656):373-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14726591" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Bacterial Proteins/*chemistry/metabolism ; Binding Sites ; Catalysis ; Crystallography, X-Ray ; Dimerization ; Guanosine Triphosphate/*analogs & derivatives/metabolism ; Heterotrimeric GTP-Binding Proteins/*chemistry/metabolism ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Models, Molecular ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Protein Subunits ; Receptors, Cytoplasmic and Nuclear/*chemistry/metabolism ; Signal Recognition Particle/*chemistry/metabolism ; Thermus/*chemistry
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  • 44
    Publication Date: 2004-10-30
    Description: Thiamine diphosphate (ThDP) is used as a cofactor in many key metabolic enzymes. We present evidence that the ThDPs in the two active sites of the E1 (EC 1.2.4.1) component of the pyruvate dehydrogenase complex communicate over a distance of 20 angstroms by reversibly shuttling a proton through an acidic tunnel in the protein. This "proton wire" permits the co-factors to serve reciprocally as general acid/base in catalysis and to switch the conformation of crucial active-site peptide loops. This synchronizes the progression of chemical events and can account for the oligomeric organization, conformational asymmetry, and "ping-pong" kinetic properties of E1 and other thiamine-dependent enzymes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Frank, Rene A W -- Titman, Christopher M -- Pratap, J Venkatesh -- Luisi, Ben F -- Perham, Richard N -- New York, N.Y. -- Science. 2004 Oct 29;306(5697):872-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15514159" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Substitution ; Binding Sites ; Catalysis ; Crystallography, X-Ray ; Dihydrolipoyllysine-Residue Acetyltransferase ; Geobacillus stearothermophilus/*enzymology ; Hydrogen-Ion Concentration ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Models, Molecular ; Mutation ; Phosphorylation ; Protein Conformation ; Protein Folding ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Protein Subunits/chemistry/metabolism ; Protons ; Pyruvate Dehydrogenase (Lipoamide)/*chemistry/genetics/*metabolism ; Pyruvate Dehydrogenase Complex/*chemistry/*metabolism ; Pyruvic Acid/metabolism ; Thiamine Pyrophosphate/*metabolism
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  • 45
    Publication Date: 2004-07-17
    Description: Resistance to the ABL kinase inhibitor imatinib (STI571 or Gleevec) in chronic myeloid leukemia (CML) occurs through selection for tumor cells harboring BCR-ABL kinase domain point mutations that interfere with drug binding. Crystallographic studies predict that most imatinib-resistant mutants should remain sensitive to inhibitors that bind ABL with less stringent conformational requirements. BMS-354825 is an orally bioavailable ABL kinase inhibitor with two-log increased potency relative to imatinib that retains activity against 14 of 15 imatinib-resistant BCR-ABL mutants. BMS-354825 prolongs survival of mice with BCR-ABL-driven disease and inhibits proliferation of BCR-ABL-positive bone marrow progenitor cells from patients with imatinib-sensitive and imatinib-resistant CML. These data illustrate how molecular insight into kinase inhibitor resistance can guide the design of second-generation targeted therapies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Shah, Neil P -- Tran, Chris -- Lee, Francis Y -- Chen, Ping -- Norris, Derek -- Sawyers, Charles L -- New York, N.Y. -- Science. 2004 Jul 16;305(5682):399-401.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Hematology and Oncology, Department of Medicine, The David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15256671" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Substitution ; Animals ; Antineoplastic Agents/metabolism/*pharmacology/therapeutic use ; Benzamides ; Binding Sites ; Cell Division/drug effects ; Cell Line ; Clinical Trials, Phase I as Topic ; Dasatinib ; Drug Resistance, Neoplasm ; Enzyme Inhibitors/metabolism/pharmacology/therapeutic use ; Fusion Proteins, bcr-abl/*antagonists & inhibitors/chemistry/genetics/metabolism ; Hematopoietic Stem Cells/drug effects ; Humans ; Imatinib Mesylate ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/*drug therapy ; Mice ; Mice, SCID ; Mutation ; Piperazines/*pharmacology/therapeutic use ; Protein Conformation ; Pyrimidines/metabolism/*pharmacology/therapeutic use ; Thiazoles/metabolism/*pharmacology/therapeutic use ; Transfection
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  • 46
    Publication Date: 2004-10-16
    Description: We have analyzed the local structure and dynamics of the prokaryotic voltage-dependent K+ channel (KvAP) at 0 millivolts, using site-directed spin labeling and electron paramagnetic resonance spectroscopy. We show that the S4 segment is located at the protein/lipid interface, with most of its charges protected from the lipid environment. Structurally, S4 is highly dynamic and is separated into two short helices by a flexible linker. Accessibility and dynamics data indicate that the S1 segment is surrounded by other parts of the protein. We propose that S1 is at the contact interface between the voltage-sensing and pore domains. These results establish the general principles of voltage-dependent channel structure in a biological membrane.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cuello, Luis G -- Cortes, D Marien -- Perozo, Eduardo -- New York, N.Y. -- Science. 2004 Oct 15;306(5695):491-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22906, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15486302" target="_blank"〉PubMed〈/a〉
    Keywords: Electron Spin Resonance Spectroscopy ; Hydrophobic and Hydrophilic Interactions ; *Lipid Bilayers ; Models, Molecular ; Oxygen ; Potassium Channels, Voltage-Gated/*chemistry/*metabolism ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary
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  • 47
    Publication Date: 2004-07-31
    Description: Argonaute proteins and small interfering RNAs (siRNAs) are the known signature components of the RNA interference effector complex RNA-induced silencing complex (RISC). However, the identity of "Slicer," the enzyme that cleaves the messenger RNA (mRNA) as directed by the siRNA, has not been resolved. Here, we report the crystal structure of the Argonaute protein from Pyrococcus furiosus at 2.25 angstrom resolution. The structure reveals a crescent-shaped base made up of the amino-terminal, middle, and PIWI domains. The Piwi Argonaute Zwille (PAZ) domain is held above the base by a "stalk"-like region. The PIWI domain (named for the protein piwi) is similar to ribonuclease H, with a conserved active site aspartate-aspartate-glutamate motif, strongly implicating Argonaute as "Slicer." The architecture of the molecule and the placement of the PAZ and PIWI domains define a groove for substrate binding and suggest a mechanism for siRNA-guided mRNA cleavage.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Song, Ji-Joon -- Smith, Stephanie K -- Hannon, Gregory J -- Joshua-Tor, Leemor -- New York, N.Y. -- Science. 2004 Sep 3;305(5689):1434-7. Epub 2004 Jul 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Watson School of Biological Sciences, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15284453" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Archaeal Proteins/*chemistry/metabolism ; Binding Sites ; Catalytic Domain ; Crystallography, X-Ray ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Pyrococcus furiosus/*chemistry ; *RNA Interference ; RNA, Messenger/*metabolism ; RNA, Small Interfering/*metabolism ; RNA-Induced Silencing Complex/*metabolism ; Ribonuclease H/chemistry
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  • 48
    Publication Date: 2004-08-21
    Description: Cartilaginous fish are the phylogenetically oldest living organisms known to possess components of the vertebrate adaptive immune system. Key to their immune response are heavy-chain, homodimeric immunoglobulins called new antigen receptors (IgNARs), in which the variable (V) domains recognize antigens with only a single immunoglobulin domain, akin to camelid heavy-chain V domains. The 1.45 angstrom resolution crystal structure of the type I IgNAR V domain in complex with hen egg-white lysozyme (HEL) reveals a minimal antigen-binding domain that contains only two of the three conventional complementarity-determining regions but still binds HEL with nanomolar affinity by means of a binding interface comparable in size to conventional antibodies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stanfield, Robyn L -- Dooley, Helen -- Flajnik, Martin F -- Wilson, Ian A -- GM38273/GM/NIGMS NIH HHS/ -- RR06603/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2004 Sep 17;305(5691):1770-3. Epub 2004 Aug 19.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15319492" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Complementarity Determining Regions/chemistry ; Crystallography, X-Ray ; Dimerization ; Drug Combinations ; Evolution, Molecular ; Genes, Immunoglobulin ; Immunoglobulin Heavy Chains/*chemistry/genetics/metabolism ; Immunoglobulin Variable Region/*chemistry/genetics/immunology/metabolism ; Immunoglobulins/*chemistry/genetics/immunology/metabolism ; Meglumine ; Models, Molecular ; Muramidase/*chemistry/immunology/metabolism ; Protein Conformation ; Protein Folding ; Protein Structure, Tertiary ; Receptors, Antigen/*chemistry/genetics/immunology/metabolism ; Sharks/*immunology ; Tetrahydropapaveroline/*analogs & derivatives
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  • 49
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-02-28
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉deHaseth, Pieter L -- Nilsen, Timothy W -- New York, N.Y. -- Science. 2004 Feb 27;303(5662):1307-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉RNA Center and Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA. pld2@po.cwru.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14988541" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Motifs ; Conserved Sequence ; DNA, Bacterial/chemistry/genetics/*metabolism ; DNA, Superhelical/chemistry/metabolism ; DNA-Directed RNA Polymerases/chemistry/*metabolism ; Escherichia coli/*enzymology/*genetics ; Models, Molecular ; Nucleic Acid Conformation ; *Promoter Regions, Genetic ; Protein Conformation ; Sigma Factor/chemistry/*metabolism ; Templates, Genetic ; Transcription, Genetic
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  • 50
    Publication Date: 2004-07-17
    Description: Interaction of regulatory DNA binding proteins with their target sites is usually preceded by binding to nonspecific DNA. This speeds up the search for the target site by several orders of magnitude. We report the solution structure and dynamics of the complex of a dimeric lac repressor DNA binding domain with nonspecific DNA. The same set of residues can switch roles from a purely electrostatic interaction with the DNA backbone in the nonspecific complex to a highly specific binding mode with the base pairs of the cognate operator sequence. The protein-DNA interface of the nonspecific complex is flexible on biologically relevant time scales that may assist in the rapid and efficient finding of the target site.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kalodimos, Charalampos G -- Biris, Nikolaos -- Bonvin, Alexandre M J J -- Levandoski, Marc M -- Guennuegues, Marc -- Boelens, Rolf -- Kaptein, Robert -- GM 23467/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Jul 16;305(5682):386-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15256668" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/*chemistry/*metabolism ; Base Pairing ; Binding Sites ; DNA, Bacterial/*chemistry/*metabolism ; Diffusion ; Dimerization ; Escherichia coli/chemistry/genetics/metabolism ; Escherichia coli Proteins/chemistry/metabolism ; Hydrogen Bonding ; Lac Repressors ; Models, Molecular ; Nuclear Magnetic Resonance, Biomolecular ; Nucleic Acid Conformation ; Operator Regions, Genetic ; Protein Binding ; Protein Conformation ; Protein Structure, Tertiary ; Repressor Proteins/*chemistry/*metabolism ; Static Electricity ; Thermodynamics
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  • 51
    Publication Date: 2004-07-17
    Description: Cytochromes P450 (P450s) metabolize a wide range of endogenous compounds and xenobiotics, such as pollutants, environmental compounds, and drug molecules. The microsomal, membrane-associated, P450 isoforms CYP3A4, CYP2D6, CYP2C9, CYP2C19, CYP2E1, and CYP1A2 are responsible for the oxidative metabolism of more than 90% of marketed drugs. Cytochrome P450 3A4 (CYP3A4) metabolizes more drug molecules than all other isoforms combined. Here we report three crystal structures of CYP3A4: unliganded, bound to the inhibitor metyrapone, and bound to the substrate progesterone. The structures revealed a surprisingly small active site, with little conformational change associated with the binding of either compound. An unexpected peripheral binding site is identified, located above a phenylalanine cluster, which may be involved in the initial recognition of substrates or allosteric effectors.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Williams, Pamela A -- Cosme, Jose -- Vinkovic, Dijana Matak -- Ward, Alison -- Angove, Hayley C -- Day, Philip J -- Vonrhein, Clemens -- Tickle, Ian J -- Jhoti, Harren -- New York, N.Y. -- Science. 2004 Jul 30;305(5684):683-6. Epub 2004 Jul 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Astex Technology, 436 Cambridge Science Park, Milton Road, Cambridge, CB4 0QA, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15256616" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Crystallization ; Crystallography, X-Ray ; Cytochrome P-450 CYP3A ; Cytochrome P-450 Enzyme System/*chemistry/*metabolism ; Heme/chemistry ; Humans ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Ligands ; Metyrapone/*metabolism ; Models, Molecular ; Phenylalanine/chemistry/metabolism ; Progesterone/*metabolism ; Protein Binding ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Water/metabolism
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  • 52
    Publication Date: 2004-08-07
    Description: The structure of epothilone A, bound to alpha,beta-tubulin in zinc-stabilized sheets, was determined by a combination of electron crystallography at 2.89 angstrom resolution and nuclear magnetic resonance-based conformational analysis. The complex explains both the broad-based epothilone structure-activity relationship and the known mutational resistance profile. Comparison with Taxol shows that the longstanding expectation of a common pharmacophore is not met, because each ligand exploits the tubulin-binding pocket in a unique and independent manner.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nettles, James H -- Li, Huilin -- Cornett, Ben -- Krahn, Joseph M -- Snyder, James P -- Downing, Kenneth H -- New York, N.Y. -- Science. 2004 Aug 6;305(5685):866-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular and Systems Pharmacology, Emory University, Atlanta, GA 30322, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15297674" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Crystallography ; Crystallography, X-Ray ; Epothilones/chemistry/*metabolism/pharmacology ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Ligands ; Models, Molecular ; Molecular Conformation ; Molecular Structure ; Mutation ; Nuclear Magnetic Resonance, Biomolecular ; Paclitaxel/metabolism ; Protein Conformation ; Stereoisomerism ; Structure-Activity Relationship ; Tubulin/chemistry/genetics/*metabolism
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  • 53
    Publication Date: 2004-03-20
    Description: Protein kinases are targets for treatment of a number of diseases. This review focuses on kinase inhibitors that are in the clinic or in clinical trials and for which structural information is available. Structures have informed drug design and have illuminated the mechanism of inhibition. We review progress with the receptor tyrosine kinases (growth factor receptors EGFR, VEGFR, and FGFR) and nonreceptor tyrosine kinases (Bcr-Abl), where advances have been made with cancer therapeutic agents such as Herceptin and Gleevec. Among the serine-threonine kinases, p38, Rho-kinase, cyclin-dependent kinases, and Chk1 have been targeted with productive results for inflammation and cancer. Structures have provided insights into targeting the inactive or active form of the kinase, for targeting the global constellation of residues at the ATP site or less conserved additional pockets or single residues, and into targeting noncatalytic domains.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Noble, Martin E M -- Endicott, Jane A -- Johnson, Louise N -- New York, N.Y. -- Science. 2004 Mar 19;303(5665):1800-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Molecular Biophysics, Department of Biochemistry, Rex Richards Building, University of Oxford, Oxford 3X2 3QU, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15031492" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Triphosphate/metabolism ; Antineoplastic Agents/chemistry/pharmacology/therapeutic use ; Binding Sites ; Catalytic Domain ; Clinical Trials as Topic ; *Drug Design ; Enzyme Inhibitors/*chemistry/metabolism/pharmacology/therapeutic use ; Humans ; Models, Molecular ; Molecular Structure ; Protein Conformation ; *Protein Kinase Inhibitors ; Protein Kinases/*chemistry/metabolism ; Protein Structure, Tertiary ; Signal Transduction/drug effects ; Structure-Activity Relationship
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  • 54
    Publication Date: 2004-05-08
    Description: Neurotrophins are secreted growth factors critical for the development and maintenance of the vertebrate nervous system. Neurotrophins activate two types of cell surface receptors, the Trk receptor tyrosine kinases and the shared p75 neurotrophin receptor. We have determined the 2.4 A crystal structure of the prototypic neurotrophin, nerve growth factor (NGF), complexed with the extracellular domain of p75. Surprisingly, the complex is composed of an NGF homodimer asymmetrically bound to a single p75. p75 binds along the homodimeric interface of NGF, which disables NGF's symmetry-related second p75 binding site through an allosteric conformational change. Thus, neurotrophin signaling through p75 may occur by disassembly of p75 dimers and assembly of asymmetric 2:1 neurotrophin/p75 complexes, which could potentially engage a Trk receptor to form a trimolecular signaling complex.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉He, Xiao-Lin -- Garcia, K Christopher -- New York, N.Y. -- Science. 2004 May 7;304(5672):870-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departments of Microbiology and Immunology, and Structural Biology, Stanford University School of Medicine, Fairchild D319, 299 Campus Drive, Stanford, CA 94305-5124, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15131306" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Site ; Amino Acid Sequence ; Animals ; Binding Sites ; Calorimetry ; Chromatography, Gel ; Crystallography, X-Ray ; Cysteine/chemistry ; Dimerization ; Humans ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Lasers ; Ligands ; Molecular Sequence Data ; Molecular Weight ; Nerve Growth Factor/*chemistry/*metabolism ; Protein Binding ; Protein Conformation ; Protein Structure, Tertiary ; Rats ; Receptor, Nerve Growth Factor ; Receptor, trkA/chemistry/metabolism ; Receptors, Nerve Growth Factor/*chemistry/*metabolism ; Recombinant Proteins/chemistry/metabolism ; Scattering, Radiation ; Signal Transduction ; Thermodynamics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 55
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    Unknown
    American Association for the Advancement of Science (AAAS)
    Publication Date: 2004-05-08
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zampieri, Niccolo -- Chao, Moses V -- New York, N.Y. -- Science. 2004 May 7;304(5672):833-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15131296" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Crystallography, X-Ray ; Dimerization ; Ligands ; Nerve Growth Factor/*chemistry/*metabolism ; Protein Binding ; Protein Conformation ; Protein Precursors/chemistry/metabolism ; Protein Structure, Tertiary ; Receptor, Nerve Growth Factor ; Receptor, trkA/chemistry/metabolism ; Receptors, Nerve Growth Factor/*chemistry/*metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 56
    Publication Date: 2004-12-25
    Description: P-type ATPases extract energy by hydrolysis of adenosine triphosphate (ATP) in two steps, formation and breakdown of a covalent phosphoenzyme intermediate. This process drives active transport and countertransport of the cation pumps. We have determined the crystal structure of rabbit sarcoplasmic reticulum Ca2+ adenosine triphosphatase in complex with aluminum fluoride, which mimics the transition state of hydrolysis of the counterion-bound (protonated) phosphoenzyme. On the basis of structural analysis and biochemical data, we find this form to represent an occluded state of the proton counterions. Hydrolysis is catalyzed by the conserved Thr-Gly-Glu-Ser motif, and it exploits an associative nucleophilic reaction mechanism of the same type as phosphoryl transfer from ATP. On this basis, we propose a general mechanism of occluded transition states of Ca2+ transport and H+ countertransport coupled to phosphorylation and dephosphorylation, respectively.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Olesen, Claus -- Sorensen, Thomas Lykke-Moller -- Nielsen, Rikke Christina -- Moller, Jesper Vuust -- Nissen, Poul -- New York, N.Y. -- Science. 2004 Dec 24;306(5705):2251-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Centre for Structural Biology, Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15618517" target="_blank"〉PubMed〈/a〉
    Keywords: Adenosine Diphosphate/chemistry/metabolism ; Adenosine Triphosphate/metabolism ; Aluminum Compounds/chemistry ; Amino Acid Motifs ; Animals ; Binding Sites ; Biological Transport, Active ; Calcium/metabolism ; Calcium-Transporting ATPases/*chemistry/*metabolism ; Chemistry, Physical ; Crystallization ; Crystallography, X-Ray ; Cytoplasm/metabolism ; Fluorides/chemistry ; Hydrolysis ; Ion Transport ; Models, Chemical ; Models, Molecular ; Phosphorylation ; Physicochemical Phenomena ; Protein Conformation ; Protein Structure, Tertiary ; *Protons ; Rabbits ; Sarcoplasmic Reticulum/enzymology ; Thapsigargin ; Thermodynamics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 57
    Publication Date: 2004-02-07
    Description: Photosynthesis uses light energy to drive the oxidation of water at an oxygen-evolving catalytic site within photosystem II (PSII). We report the structure of PSII of the cyanobacterium Thermosynechococcus elongatus at 3.5 angstrom resolution. We have assigned most of the amino acid residues of this 650-kilodalton dimeric multisubunit complex and refined the structure to reveal its molecular architecture. Consequently, we are able to describe details of the binding sites for cofactors and propose a structure of the oxygen-evolving center (OEC). The data strongly suggest that the OEC contains a cubane-like Mn3CaO4 cluster linked to a fourth Mn by a mono-micro-oxo bridge. The details of the surrounding coordination sphere of the metal cluster and the implications for a possible oxygen-evolving mechanism are discussed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ferreira, Kristina N -- Iverson, Tina M -- Maghlaoui, Karim -- Barber, James -- Iwata, So -- F32 GM068304/GM/NIGMS NIH HHS/ -- F32 GM068304-01/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2004 Mar 19;303(5665):1831-8. Epub 2004 Feb 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Imperial College London, London, SW7 2AZ, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/14764885" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Calcium/analysis/chemistry/metabolism ; Carotenoids/chemistry/metabolism ; Chlorophyll/chemistry/metabolism ; Crystallization ; Crystallography, X-Ray ; Cyanobacteria/*enzymology ; Dimerization ; Electron Transport ; Free Radicals ; Histidine/chemistry/metabolism ; Hydrogen Bonding ; Ligands ; Manganese/analysis/chemistry/metabolism ; Models, Chemical ; Models, Molecular ; Oxidation-Reduction ; Oxygen/*metabolism ; Photosynthetic Reaction Center Complex Proteins/chemistry/metabolism ; Photosystem II Protein Complex/*chemistry/*metabolism ; Protein Conformation ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Protein Subunits/chemistry ; Tyrosine/*analogs & derivatives/chemistry/metabolism ; Water/*metabolism ; beta Carotene/chemistry/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 58
    Publication Date: 2011-08-24
    Description: Carbon nanotubes (CNTs) used as a probe for scanning probe microscopy has become one of the many potential usages of CNTs that is finding real applications in scientific research and industrial communities. It has been proposed that the unique mechanical buckling properties of the CNT would lessen the imaging force exerted on the sample and, thus, make CNT scanning probes ideal for imaging soft materials, including biological samples in liquid environments. The hydrophobic nature of the CNT graphitic sidewall is clearly chemically incompatible with the aqueous solution requirements in some biological imaging applications. In this paper, we present electron micrograph results demonstrating the instability of CNT scanning probes when submerged in aqueous solution. Moreover, we also introduce a novel approach to resolve this chemical incompatibility problem. By coating the CNT probe with ethylenediamine, thus rendering the CNT probe less hydrophobic, we demonstrate the liquid imaging capability of treated CNT probes. Experimental data for imaging in aqueous solutions are presented, which include an ultrathin Ir film and DNA molecules on a mica surface.
    Keywords: Life Sciences (General)
    Type: IEEE Trans Nanobioscience (ISSN 1536-1241); Volume 3; 1; 56-60
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  • 59
    Publication Date: 2011-08-24
    Description: Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.
    Keywords: Life Sciences (General)
    Type: HortScience : a publication of the American Society for Horticultural Science (ISSN 0018-5345); Volume 39; 7; 1541-5
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  • 60
    Publication Date: 2011-08-24
    Description: The productivity of lettuce in a combination of high light, high temperature, and elevated CO2 has not been commonly studied because rapid growth usually causes a calcium deficiency in meristems called tipburn, which greatly reduces quality and marketability. We eliminated tipburn by blowing air directly onto the meristem, which allowed us to increase the photosynthetic photon flux (PPF) to 1000 micromoles m-2 s-1 (57.6 mol m-2 d-1); two to three times higher than normally used for lettuce. Eliminating tipburn doubled edible yield at the highest PPF level. In addition to high PPF, CO2 was elevated to 1200 micromoles m-2 mol-1, which increased the temperature optimum from 25 to 30 degrees C. The higher temperature increased leaf expansion rate, which improved radiation capture and more than doubled yield. Photosynthetic efficiency, measured as canopy quantum yield in a whole-plant gas exchange system, steadily increased up to the highest temperature of 32 degrees C in high CO2. The highest productivity was 19 g m-2 d-1 of dry biomass (380 g d-1 fresh mass) averaged over the 23 days the plants received light. Without the limitation of tipburn, the combination of high PPF, high temperature, and elevated CO2 resulted in a 4-fold increase in growth rate over productivity in conventional environments.
    Keywords: Life Sciences (General)
    Type: Journal of the American Society for Horticultural Science. American Society for Horticultural Science (ISSN 0003-1062); Volume 129; 3; 331-8
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  • 61
    Publication Date: 2011-08-24
    Description: Nanomaterials are part of an industrial revolution to develop lightweight but strong materials for a variety of purposes. Single-wall carbon nanotubes are an important member of this class of materials. They structurally resemble rolled-up graphite sheets, usually with one end capped; individually they are about 1 nm in diameter and several microns long, but they often pack tightly together to form rods or ropes of microscopic sizes. Carbon nanotubes possess unique electrical, mechanical, and thermal properties and have many potential applications in the electronics, computer, and aerospace industries. Unprocessed nanotubes are very light and could become airborne and potentially reach the lungs. Because the toxicity of nanotubes in the lung is not known, their pulmonary toxicity was investigated. The three products studied were made by different methods and contained different types and amounts of residual catalytic metals. Mice were intratracheally instilled with 0, 0.1, or 0.5 mg of carbon nanotubes, a carbon black negative control, or a quartz positive control and euthanized 7 d or 90 d after the single treatment for histopathological study of the lungs. All nanotube products induced dose-dependent epithelioid granulomas and, in some cases, interstitial inflammation in the animals of the 7-d groups. These lesions persisted and were more pronounced in the 90-d groups; the lungs of some animals also revealed peribronchial inflammation and necrosis that had extended into the alveolar septa. The lungs of mice treated with carbon black were normal, whereas those treated with high-dose quartz revealed mild to moderate inflammation. These results show that, for the test conditions described here and on an equal-weight basis, if carbon nanotubes reach the lungs, they are much more toxic than carbon black and can be more toxic than quartz, which is considered a serious occupational health hazard in chronic inhalation exposures.
    Keywords: Life Sciences (General)
    Type: Toxicological sciences : an official journal of the Society of Toxicology (ISSN 1096-6080); Volume 77; 1; 126-34
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  • 62
    Publication Date: 2011-08-24
    Description: Rapid microbial monitoring technologies are invaluable in assessing contamination of spacecraft and associated environments. Universal and widespread elements of microbial structure and chemistry are logical targets for assessing microbial burden. Several biomarkers such as ATP, LPS, and DNA (ribosomal or spore-specific), were targeted to quantify either total bioburden or specific types of microbial contamination. The findings of these assays were compared with conventional, culture-dependent methods. This review evaluates the applicability and efficacy of some of these methods in monitoring the microbial burden of spacecraft and associated environments. Samples were collected from the surfaces of spacecraft, from surfaces of assembly facilities, and from drinking water reservoirs aboard the International Space Station (ISS). Culture-dependent techniques found species of Bacillus to be dominant on these surfaces. In contrast, rapid, culture-independent techniques revealed the presence of many Gram-positive and Gram-negative microorganisms, as well as actinomycetes and fungi. These included both cultivable and noncultivable microbes, findings further confirmed by DNA-based microbial detection techniques. Although the ISS drinking water was devoid of cultivable microbes, molecular-based techniques retrieved DNA sequences of numerous opportunistic pathogens. Each of the methods tested in this study has its advantages, and by coupling two or more of these techniques even more reliable information as to microbial burden is rapidly obtained. Copyright 2004 Springer-Verlag.
    Keywords: Life Sciences (General)
    Type: Microbial ecology (ISSN 0095-3628); Volume 47; 2; 150-8
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  • 63
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-24
    Description: The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., 〈1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 34; 6; 1441-50
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  • 64
    Publication Date: 2011-08-24
    Description: The latest process for producing large quantities of single-walled carbon nanotubes (SWNTs) to emerge from the Rice University, dubbed HiPco, is living up to its promise. The current production rates approach 450 mg/h (or 10 g/day), and nanotubes typically have no more than 7 mol % of iron impurities. Second-generation HiPco apparatus can run continuously for 7-10 days at a time. In the HiPco process nanotubes grow in high-pressure, high-temperature flowing CO on catalytic clusters of iron. Catalyst is formed in situ by thermal decomposition of iron pentacarbonyl, which is delivered intact within a cold CO flow and then rapidly mixed with hot CO in the reaction zone. Upon heating, the Fe(CO)5 decomposes into atoms that condense into larger clusters. SWNTs nucleate and grow on these particles in the gas phase via CO disproportionation: CO + CO --〉 CO2 + C (SWNT), catalyzed by the Fe surface. The concentration of CO2 produced in this reaction is equal to that of carbon and can therefore serve as a useful real-time feedback parameter. It was used to study and optimize SWNT production as a function of temperature, pressure, and Fe(CO)5 concentration. The results of the parametric study are in agreement with current understanding of the nanotube formation mechanism.
    Keywords: Life Sciences (General)
    Type: Journal of nanoscience and nanotechnology (ISSN 1533-4880); Volume 4; 4; 307-16
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  • 65
    Publication Date: 2011-08-24
    Description: Chemical kinetic models for the nucleation and growth of clusters and single-walled carbon nanotube (SWNT) growth are developed for numerical simulations of the production of SWNTs. Two models that involve evaporation and condensation of carbon and metal catalysts, a full model involving all carbon clusters up to C80, and a reduced model are discussed. The full model is based on a fullerene model, but nickel and carbon/nickel cluster reactions are added to form SWNTs from soot and fullerenes. The full model has a large number of species--so large that to incorporate them into a flow field computation for simulating laser ablation and arc processes requires that they be simplified. The model is reduced by defining large clusters that represent many various sized clusters. Comparisons are given between these models for cases that may be applicable to arc and laser ablation production. Solutions to the system of chemical rate equations of these models for a ramped temperature profile show that production of various species, including SWNTs, agree to within about 50% for a fast ramp, and within 10% for a slower temperature decay time.
    Keywords: Life Sciences (General)
    Type: Journal of nanoscience and nanotechnology (ISSN 1533-4880); Volume 4; 4; 368-76
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  • 66
    Publication Date: 2011-08-24
    Description: The cWINNOWER algorithm detects fuzzy motifs in DNA sequences rich in protein-binding signals. A signal is defined as any short nucleotide pattern having up to d mutations differing from a motif of length l. The algorithm finds such motifs if a clique consisting of a sufficiently large number of mutated copies of the motif (i.e., the signals) is present in the DNA sequence. The cWINNOWER algorithm substantially improves the sensitivity of the winnower method of Pevzner and Sze by imposing a consensus constraint, enabling it to detect much weaker signals. We studied the minimum detectable clique size qc as a function of sequence length N for random sequences. We found that qc increases linearly with N for a fast version of the algorithm based on counting three-member sub-cliques. Imposing consensus constraints reduces qc by a factor of three in this case, which makes the algorithm dramatically more sensitive. Our most sensitive algorithm, which counts four-member sub-cliques, needs a minimum of only 13 signals to detect motifs in a sequence of length N = 12,000 for (l, d) = (15, 4). Copyright Imperial College Press.
    Keywords: Life Sciences (General)
    Type: J Bioinform Comput Biol (ISSN 0219-7200); Volume 2; 1; 47-60
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  • 67
    Publication Date: 2011-08-24
    Description: Different types of lasers are now routinely used to prepare single-walled carbon nanotubes. The original method developed by researchers at Rice University used a "double-pulse laser oven" process. Several researchers have used variations of the lasers to include one-laser pulse (green or infrared), different pulse widths (ns to micros as well as continuous wave), and different laser wavelengths (e.g., CO2, or free electron lasers in the near to far infrared). Some of these variations are tried with different combinations and concentrations of metal catalysts, buffer gases (e.g., helium), oven temperatures, flow conditions, and even different porosities of the graphite targets. This article is an attempt to cover all these variations and their relative merits. Possible growth mechanisms under these different conditions will also be discussed.
    Keywords: Life Sciences (General)
    Type: Journal of nanoscience and nanotechnology (ISSN 1533-4880); Volume 4; 4; 317-25
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  • 68
    Publication Date: 2011-08-24
    Description: BACKGROUND: Reducing cost and time is the major concern in clinical diagnostics, particularly in molecular diagnostics. Miniaturization technologies have been recognized as promising solutions to provide low-cost microchips for diagnostics. With the recent advancement in nanotechnologies, it is possible to further improve detection sensitivity and simplify sample preparation by incorporating nanoscale elements in diagnostics devices. A fusion of micro- and nanotechnologies with biology has great potential for the development of low-cost disposable chips for rapid molecular analysis that can be carried out with simple handheld devices. APPROACH: Vertically aligned multiwalled carbon nanotubes (MWNTs) are fabricated on predeposited microelectrode pads and encapsulated in SiO2 dielectrics with only the very end exposed at the surface to form an inlaid nanoelectrode array (NEA). The NEA is used to collect the electrochemical signal associated with the target molecules binding to the probe molecules, which are covalently attached to the end of the MWNTs. CONTENT: A 3 x 3 microelectrode array is presented to demonstrate the miniaturization and multiplexing capability. A randomly distributed MWNT NEA is fabricated on each microelectrode pad. Selective functionalization of the MWNT end with a specific oligonucleotide probe and passivation of the SiO2 surface with ethylene glycol moieties are discussed. Ru(bpy)2+ -mediator-amplified guanine oxidation is used to directly measure the electrochemical signal associated with target molecules. SUMMARY: The discussed MWNT NEAs have ultrahigh sensitivity in direct electrochemical detection of guanine bases in the nucleic acid target. Fewer than approximately 1000 target nucleic acid molecules can be measured with a single microelectrode pad of approximately 20 x 20 microm2, which approaches the detection limit of laser scanners in fluorescence-based DNA microarray techniques. MWNT NEAs can be easily integrated with microelectronic circuitry and microfluidics for development of a fully automated system for rapid molecular analysis with minimum cost.
    Keywords: Life Sciences (General)
    Type: Clinical chemistry (ISSN 0009-9147); Volume 50; 10; 1886-93
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  • 69
    Publication Date: 2011-08-24
    Description: A detailed study was made of the biological cleaning effectiveness, defined in terms of the ability to remove bacterial spores, of a number of methods used to clean hardware surfaces. Aluminum (Al 6061) and titanium (Ti 6Al-4V) were chosen for the study as they were deemed the two materials most likely to be used in spacecraft extraterrestrial sampler construction. Metal coupons (1 cm x 2.5 cm) were precleaned and inoculated with 5.8 x 10(3) cultivable Bacillus subtilis spores, which are commonly found on spacecraft surfaces and in the assembly environments. The inoculated coupons were subsequently cleaned using: (1) 70% isopropyl alcohol wipe; (2) water wipe; (3) multiple-solvent flight-hardware cleaning procedures used at the Jet Propulsion Laboratory (JPL); (4) Johnson Space Center-developed ultrapure water rinse; and (5) a commercial, semi-aqueous, multiple-solvent (SAMS) cleaning process. The biological cleaning effectiveness was measured by agar plate assay, sterility test (growing in liquid media), and epifluorescent microscopy. None of the cleaning protocols tested completely removed viable spores from the surface of the aluminum. In contrast, titanium was capable of being cleaned to sterility by two methods, the JPL standard and the commercial SAMS cleaning process. Further investigation showed that the passivation step employed in the JPL standard method is an effective surface sterilant on both metals but not compatible with aluminum. It is recommended that titanium (Ti 6Al-4V) be considered superior to aluminum (Al 6061) for use in spacecraft sampling hardware, both for its potential to be cleaned to sterilization and for its ability to withstand the most effective cleaning protocols.
    Keywords: Life Sciences (General)
    Type: Astrobiology (ISSN 1531-1074); Volume 4; 3; 377-90
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  • 70
    Publication Date: 2011-08-24
    Description: Zoological data and a growing mythology contributed to ancient Western knowledge about large serpents. Yet little modern attention has been paid to the sources, transmission, and receipt in the early Middle Ages of the ancients' information concerning "dragons" and "sea serpents." Real animals--primarily pythons and whales--lie behind the ancient stories. Other animals, conflations of different animals, simple misunderstandings, and willful exaggerations are found to account for the fanciful embellishments, but primitive myths played no significant role in this process during classical times. The expedition of Alexander the Great into India (327-325 B.C.) and the Bagradas River incident in North Africa (256 B.C.) had enormous repercussions on the development of serpent lore. Credible evidence is found for the presence of ancient populations of pythons living along the North African coast west of Egypt and along the coast of the Arabian Sea between the Indus River and the Strait of Hormuz--places where they no longer exist today. The maximum sizes of ancient pythons may have been greater than those of today's specimens.
    Keywords: Life Sciences (General)
    Type: Isis; an international review devoted to the history of science and its cultural influences (ISSN 0021-1753); Volume 95; 2; 220-38
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  • 71
    Publication Date: 2011-08-24
    Description: The use of magnetic fluids and magnetic particles in combinatorial hyperthermia therapy for cancer treatment is reviewed. The investigation approach adopted for producing thermoregulating particles and tissue model studies for studying particle retention and heating characteristics is discussed.
    Keywords: Life Sciences (General)
    Type: Annals of the New York Academy of Sciences (ISSN 0077-8923); Volume 1027; 99-109
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  • 72
    Publication Date: 2011-08-24
    Description: Robert Barany won the 1914 Nobel Prize in medicine for his convection hypothesis for caloric stimulation. Microgravity caloric tests aboard the 1983 SpaceLab 1 mission produced nystagmus results that contradicted the basic premise of Barany's convection theory. In this paper, we present a fluid structural analysis of the caloric stimulation of the lateral semicircular canal. Direct numerical simulations indicate that on earth, natural convection is the dominant mechanism for endolymphatic flow. However, in the microgravity environment of orbiting spacecraft, where buoyancy effects are mitigated, an expansive convection becomes the sole mechanism for producing endolymph motion and cupular displacement. Transient 1 g and microgravity case studies are presented to delineate the different dynamic behaviors of the 1 g and microgravity endolymphatic flows. The associated fluid-structural interactions are also analyzed based on the time evolution of cupular displacements.
    Keywords: Life Sciences (General)
    Type: Annals of the New York Academy of Sciences (ISSN 0077-8923); Volume 1027; 360-70
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  • 73
    Publication Date: 2011-08-24
    Description: Plants will be an important component of future long-term space missions. Lighting systems for growing plants will need to be lightweight, reliable, and durable, and light-emitting diodes (LEDs) have these characteristics. Previous studies demonstrated that the combination of red and blue light was an effective light source for several crops. Yet the appearance of plants under red and blue lighting is purplish gray making visual assessment of any problems difficult. The addition of green light would make the plant leave appear green and normal similar to a natural setting under white light and may also offer a psychological benefit to the crew. Green supplemental lighting could also offer benefits, since green light can better penetrate the plant canopy and potentially increase plant growth by increasing photosynthesis from the leaves in the lower canopy. In this study, four light sources were tested: 1) red and blue LEDs (RB), 2) red and blue LEDs with green fluorescent lamps (RGB), 3) green fluorescent lamps (GF), and 4) cool-white fluorescent lamps (CWF), that provided 0%, 24%, 86%, and 51% of the total PPF in the green region of the spectrum, respectively. The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control.
    Keywords: Life Sciences (General)
    Type: HortScience : a publication of the American Society for Horticultural Science (ISSN 0018-5345); Volume 39; 7; 1617-22
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  • 74
    Publication Date: 2011-08-24
    Description: ALTEA-MICE will supplement the ALTEA project on astronauts and provide information on the functional visual impairment possibly induced by heavy ions during prolonged operations in microgravity. Goals of ALTEA-MICE are: (1) to investigate the effects of heavy ions on the visual system of normal and mutant mice with retinal defects; (2) to define reliable experimental conditions for space research; and (3) to develop animal models to study the physiological consequences of space travels on humans. Remotely controlled mouse setup, applied electrophysiological recording methods, remote particle monitoring, and experimental procedures were developed and tested. The project has proved feasible under laboratory-controlled conditions comparable in important aspects to those of astronauts' exposure to particle in space. Experiments are performed at the Brookhaven National Laboratories [BNL] (Upton, NY, USA) and the Gesellschaft fur Schwerionenforschung mbH [GSI]/Biophysik (Darmstadt, FRG) to identify possible electrophysiological changes and/or activation of protective mechanisms in response to pulsed radiation. Offline data analyses are in progress and observations are still anecdotal. Electrophysiological changes after pulsed radiation are within the limits of spontaneous variability under anesthesia, with only indirect evidence of possible retinal/cortical responses. Immunostaining showed changes (e.g. increased expression of FGF2 protein in the outer nuclear layer) suggesting a retinal stress reaction to high-energy particles of potential relevance in space. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 33; 8; 1347-51
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  • 75
    Publication Date: 2011-08-24
    Description: The ALTEA project investigates the risks of functional brain damage induced by particle radiation in space. A modular facility (the ALTEA facility) is being implemented and will be operated in the International Space Station (ISS) to record electrophysiological and behavioral descriptors of brain function and to monitor their time dynamics and correlation with particles and space environment. The focus of the program will be on abnormal visual perceptions (often reported as "light flashes" by astronauts) and the impact on retinal and brain visual structures of particle in microgravity conditions. The facility will be made available to the international scientific community for human neurophysiological, electrophysiological and psychophysics experiments, studies on particle fluxes, and dosimetry. A precursor of ALTEA (the 'Alteino' project) helps set the experimental baseline for the ALTEA experiments, while providing novel information on the radiation environment onboard the ISS and on the brain electrophysiology of the astronauts during orbital flights. Alteino was flown to the ISS on the Soyuz TM34 as part of mission Marco Polo. Controlled ground experiments using mice and accelerator beams complete the experimental strategy of ALTEA. We present here the status of progress of the ALTEA project and preliminary results of the Alteino study on brain dynamics, particle fluxes and abnormal visual perceptions. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 33; 8; 1352-7
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  • 76
    Publication Date: 2011-08-24
    Description: The main goal of PUR experiment (phage and uracil response) is to examine and quantify the effect of specific space conditions on nucleic acid models. To achieve this an improved method was elaborated for the preparation of DNA and bacteriophage thin films. The homogeneity of the films was controlled by UV spectroscopy and microscopy. To provide experimental evidence for the hypothesis that interplanetary transfer of the genetic material is possible, phage T7 and isolated T7 DNA thin films have been exposed to selected space conditions: intense UVC radiation (lambda=254 nm) and high vacuum (10(-4) Pa). The effects of DNA hydration, conformation and packing on UV radiation damage were examined. Characteristic changes in the absorption spectrum, in the electrophoretic pattern of DNA and the decrease of the amount of PCR products have been detected indicating the photodamage of isolated and intraphage DNA. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 33; 8; 1306-10
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  • 77
    Publication Date: 2011-08-24
    Description: No abstract available
    Keywords: Life Sciences (General)
    Type: The Journal of eukaryotic microbiology (ISSN 1066-5234); Volume 51; 1; 3-7
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  • 78
    Publication Date: 2011-08-24
    Description: Anionic (sodium laureth sulfate, SLES), amphoteric (cocamidopropyl betaine, CAPB) and nonionic (alcohol polyethoxylate, AE) surfactants were added to separate nutrient film technique (NFT) hydroponic systems containing dwarf wheat (Triticum aestivum cv. USU Apogee) in a series of 21 day trials. Surfactant was added either in a (1). temporally dynamic mode (1-3 g surfactant m(-2) growing area d(-1)) as effected by automatic addition of a 300 ppm surfactant solution to meet plant water demand, or (2). continuous mode (2 g surfactant m(-2) growing area d(-1)) as effected by slow addition (10 mLh(-1)) of a 2000 ppm surfactant solution beginning at 4d after planting. SLES showed rapid primary degradation in both experiments, with no accumulation 24 h after initial addition. CAPB and AE were degraded less rapidly, with 30-50% remaining 24 h after initial addition, but CAPB and AE levels were below detection limit for the remainder of the study. No reductions in vegetative growth of wheat were observed in response to SLES, but biomass was reduced 20-25% with CAPB and AE. Microbial communities associated with both the plant roots and wetted hardware surfaces actively degraded the surfactants, as determined by monitoring surfactant levels following pulse additions at day 20 (with plants) and day 21 (after plant removal). In order to test whether the biofilm communities could ameliorate phytotoxicity by providing a microbial community acclimated for CAPB and AE decay, the continuous exposure systems were planted with wheat seeds after crop removal at day 21. Acclimation resulted in faster primary degradation (〉90% within 24h) and reduced phytotoxicity. Overall, the studies indicate that relatively small areas (3-5m(2)) of hydroponic plant systems can process per capita production of mixed surfactants (5-10 g x person(-1)d(-1)) with minimal effects on plant growth.
    Keywords: Life Sciences (General)
    Type: Water research (ISSN 0043-1354); Volume 38; 8; 1952-62
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  • 79
    Publication Date: 2011-08-24
    Description: Mutations in BRCA1 are characterized by predisposition to breast cancer, ovarian cancer and prostate cancer as well as colon cancer. Prognosis for this cancer survival depends upon the stage at which cancer is diagnosed. Reliable and rapid mutation detection is crucial for the early diagnosis and treatment. We developed an electronic assay for the detection of a representative single nucleotide polymorphism (SNP), deletion and insertion in BRCA1 gene by the microelectronics microarray instrumentation. The assay is rapid, and it takes 30 minutes for the immobilization of target DNA samples, hybridization, washing and readout. The assay is multiplexing since it is carried out at the same temperature and buffer conditions for each step. The assay is also highly specific, as the signal-to-noise ratio is much larger than recommended value (72.86 to 321.05 vs. 5) for homozygotes genotyping, and signal ratio close to the perfect value 1 for heterozygotes genotyping (1.04).
    Keywords: Life Sciences (General)
    Type: Biomed Microdevices (ISSN 1387-2176); Volume 6; 1; 55-60
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  • 80
    Publication Date: 2011-08-24
    Description: According to D. E. Broadbent's (1958) selective filter theory, people do not process unattended stimuli beyond the analysis of basic physical properties. This theory was later rejected on the basis of numerous findings that people identify irrelevant (and supposedly unattended) stimuli. A careful review of this evidence, however, reveals strong reasons to doubt that these irrelevant stimuli were in fact unattended. This review exposed a clear need for new experiments with tight control over the locus of attention. The authors present 5 such experiments using a priming paradigm. When steps were taken to ensure that irrelevant stimuli were not attended, these stimuli produced no priming effects. Hence, the authors found no evidence that unattended stimuli can be identified. The results support a modern version of Broadbent's selective theory, updated to reflect recent research advances. 2004 APA.
    Keywords: Life Sciences (General)
    Type: Psychological review (ISSN 0033-295X); Volume 111; 4; 880-913
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  • 81
    Publication Date: 2011-08-24
    Description: We use spatially continuous satellite data as a correlate of precipitation within tropical Africa and show that the majority of documented Ebola hemorrhagic fever outbreaks were closely associated with sharply drier conditions at the end of the rainy season. We propose that these trigger events may enhance transmission of Ebola virus from its cryptic reservoir to humans. These findings suggest specific directions to help understand the sylvatic cycle of the virus and may provide early warning tools to detect possible future outbreaks of this enigmatic disease.
    Keywords: Life Sciences (General)
    Type: The American journal of tropical medicine and hygiene (ISSN 0002-9637); Volume 71; 5; 664-74
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  • 82
    Publication Date: 2011-08-24
    Description: In this paper we analyze the effects of the following phenomena associated with the thermocapillary migration of a drop. The first is the influence of Newtonian surface rheology of the interface and the second is that of the energy changes associated with stretching and shrinkage of the interfacial area elements, when the drop is in motion. The former occurs because of dissipative processes in the interfacial region, such as when surfactant molecules are adsorbed at the interface in sufficient concentration. The interface is typically modeled in this instance by ascribing to it a surface viscosity. This is a different effect from that of interfacial tension gradients arising from surfactant concentration gradients. The stretching and shrinkage of interfacial area elements leads to changes in the internal energy of these elements that affects the transport of energy in the fluids adjoining the interface. When an element on the interface is stretched, its internal energy increases because of the increase in its area. This energy is supplied by the neighboring fluids that are cooled as a consequence. Conversely, when an element on the interface shrinks, the adjoining fluids are warmed. In the case of a moving drop, elements of interfacial area are stretched in the forward half of the drop, and are shrunk in the rear half. Consequently, the temperature variation on the surface of the drop and its migration speed are modified. The analysis of the motion of a drop including these effects was first performed by LeVan in 1981, in the limit when convective transport of momentum and energy are negligible. We extend the analysis of LeVan to include the convective transport of momentum by demonstrating that an exact solution of the momentum equation is obtained for an arbitrary value of the Reynolds number. This solution is then used to calculate the slightly deformed shape of the drop from a sphere.
    Keywords: Life Sciences (General)
    Type: Annals of the New York Academy of Sciences (ISSN 0077-8923); Volume 1027; 303-10
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  • 83
    Publication Date: 2011-08-24
    Description: In order to determine the effect of the number of sonic boom occurrences on annoyance, a computer-based system was developed for studying the subjective response of people to the occurrence of simulated sonic booms in their homes. The system provided a degree of control over the noise exposure not found in community surveys and a degree of situational realism not available in the laboratory. A system was deployed for eight weeks in each of 33 homes. Each day from 4 to 63 sonic booms were played as the test subject went about his or her normal activities. At the end of the day, the test subjects rated their annoyance to the sonic booms heard during the day. The sonic booms consisted of different combinations of waveforms, levels, and occurrence rates. The experiment confirmed that the increase in annoyance resulting from multiple occurrences can be modeled by the addition of the term "10 * log(number of occurrences)" to the sonic boom level. Of several noise metrics considered, perceived level was the best annoyance predictor. Comparisons of the subjective responses to the different sonic boom waveforms found no differences that were not accounted for by the noise metrics.
    Keywords: Life Sciences (General)
    Type: The Journal of the Acoustical Society of America (ISSN 0001-4966); Volume 116; 3; 1573-84
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  • 84
    Publication Date: 2011-08-24
    Description: The noninvasive techniques of static and dynamic light scattering are emerging as valuable diagnostic tools for the early detection of ocular and systemic diseases. These include corneal abnormalities, pigmentary dispersion syndrome, glaucoma, cataract, diabetic vitreopathy, and possibly macular degeneration. Systemic conditions such as diabetes and possibly Alzheimer's disease can potentially be detected early via ocular tissues. The current state of development of these techniques for application to ophthalmic research and ultimately clinical practice is reviewed. (c) 2004 Society of Photo-Optical Instrumentation Engineers.
    Keywords: Life Sciences (General)
    Type: Journal of biomedical optics (ISSN 1083-3668); Volume 9; 1; 22-37
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  • 85
    Publication Date: 2011-08-24
    Description: A new optical scheme to detect glucose concentration in the aqueous humor of the eye is presented. The ultimate aim is to apply this technique in designing a new instrument for, routinely and frequently, noninvasively monitoring blood glucose levels in diabetic patients without contact (no index matching) between the eye and the instrument. The optical scheme exploits the Brewster reflection of circularly polarized light off of the lens of the eye. Theoretically, this reflected linearly polarized light on its way to the detector is expected to rotate its state of polarization, owing to the presence of glucose molecules in the aqueous humor of a patient's eye. An experimental laboratory setup based on this scheme was designed and tested by measuring a range of known concentrations of glucose solutions dissolved in water. (c) 2004 Society of Photo-Optical Instrumentation Engineers.
    Keywords: Life Sciences (General)
    Type: Journal of biomedical optics (ISSN 1083-3668); Volume 9; 1; 103-15
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  • 86
    Publication Date: 2011-08-24
    Description: A round-spore-forming Bacillus species that produces an exosporium was isolated from the surface of the Mars Odyssey spacecraft. This novel species has been characterized on the basis of phenotypic traits, 16S rDNA sequence analysis and DNA-DNA hybridization. According to the results of these analyses, this strain belongs to the genus Bacillus and is a Gram-positive, aerobic, rod-shaped, endospore-forming eubacterium. Ultrathin sections of the spores showed the presence of an exosporium, spore coat, cortex and core. 16S rDNA sequence similarities between this strain, Bacillus fusiformis and Bacillus silvestris were approximately 96% and DNA-DNA reassociation values with these two bacilli were 23 and 17%, respectively. Spores of the novel species were resistant to desiccation, H2O2 and UV and gamma radiation. Of all strains tested, the spores of this strain were the most consistently resistant and survived all of the challenges posed, i.e. exposure to conditions of desiccation (100% survival), H2O2 (26% survival), UV radiation (10% survival at 660 J m(-2)) and gamma radiation (0.4% survival). The name proposed for this novel bacterium is Bacillus odysseyi sp. nov.; the type strain is 34hs-1T (=ATCC PTA-4993T=NRRL B-30641T=NBRC 100172T).
    Keywords: Life Sciences (General)
    Type: International journal of systematic and evolutionary microbiology (ISSN 1466-5026); Volume 54; Pt 1; 195-201
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  • 87
    Publication Date: 2011-08-24
    Description: Orbital debris impacts on the International Space Station occur frequently. To date, none of the impacting particles has been large enough to penetrate manned pressurized volumes. We used the Manned Spacecraft Crew Survivability code to evaluate the risk to crew of penetrations of pressurized modules at two assembly stages: after Flight 1J, when the pressurized elements of Kibo, the Japanese Experiment Module, are present, and after Flight 1E, when the European Columbus Module is present. Our code is a Monte-Carlo simulation of impacts on the Station that considers several potential event types that could lead to crew loss. Among the statistics tabulated by the program is the probability of death of one or more crew members in the event of a penetration, expressed as the risk factor, R. This risk factor is dependent on details of crew operations during both ordinary circumstances and decompression emergencies, as well as on details of internal module configurations. We conducted trade studies considering these procedure and configuration details to determine the bounds on R at the 1J and 1E stages in the assembly sequence. Here we compare the R-factor bounds, and procedures could that reduce R at these stages. Published by Elsevier Ltd on behalf of COSPAR.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 34; 5; 1104-8
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  • 88
    Publication Date: 2011-08-24
    Description: Obtaining uniform mechano-dwarfing of Arabidopsis thaliana (L.) Heynh. seedlings within dense plantings is problematic. Alternative forms of mechano-stimulation were applied to seedlings in effort to obtain uniform growth reduction compared with undisturbed controls in both greenhouse and controlled growth environments. Arabidopsis grown under low photosynthetic photon flux (PPF) artificial light grew upright with limited leaf expansion, which enhanced mechano-responsiveness compared to that of rosette-growing plants under filtered sunlight or high PPF artificial light. Hypocotyls of seedlings grown at PPFs 〉 60 micromoles m-2 s-1 elongated less and had 6% less sensitivity to mechanical stress than seedlings grown at PPFs 〈 60 micromoles m-2 s-1. Fluorescent lamps alone (F) or fluorescent plus incandescent (F+I) lamps were compared for seedling responses to mechanical stress. Under F lighting, hypocotyl elongation was reduced 25% to 40% by twice-daily brush or plate treatments, and brushed seedlings exhibited more growth reduction than did plate treatments. Seedlings grown under F+I lamps exhibited similar stress-induced growth reduction compared to seedlings grown under F only, but stressed F+I seedlings lodged to a greater extent due to excessive hypocotyl elongation. Temperature-response studies using standardized F-only lighting indicated increased hypocotyl elongation but decreased leaf expansion, and decreased mechano-responsivity to brushing over the temperature range from 20 to 28 degrees C. Daylength studies indicated similar degrees of mechano-inhibition of hypocotyl elongation over the daylength range of 12, 16, 20, and 24 hours, whereas fresh weight of stressed seedling shoots declined compared to controls. A combination of environmental growth parameters that give repeatable, visual mechanical dwarfing of Arabidopsis include low-PPF fluorescent lighting from 55 to 60 micromoles m-2 s-1, ambient temperatures from 22 to 25 degrees C, and twice-daily brush treatments.
    Keywords: Life Sciences (General)
    Type: Journal of the American Society for Horticultural Science. American Society for Horticultural Science (ISSN 0003-1062); Volume 129; 3; 339-43
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  • 89
    Publication Date: 2011-08-24
    Description: Described is the Liulin-5 experiment and instrumentation, developed for investigation of the space radiation doses depth distribution in a human phantom on the Russian Segment of the International Space Station (ISS). Liulin-5 experiment is a part of the international project MATROSHKA-R on ISS. The experiment MATROSHKA-R is aimed to study the depth dose distribution at the sites of critical organs of the human body, using models of human body-anthropomorphic and spherical tissue-equivalent phantoms. The aim of Liulin-5 experiment is long term (4-5 years) investigation of the radiation environment dynamics inside the spherical tissue-equivalent phantom, mounted in different places of the Russian Segment of ISS. Energy deposition spectra, linear energy transfer spectra, flux and dose rates for protons and the biologically-relevant heavy ion components of the galactic cosmic radiation will be measured simultaneously with near real time resolution at different depths of the phantom by a telescope of silicon detectors. Data obtained together with data from other active and passive dosimeters will be used to estimate the radiation risk to the crewmembers, verify the models of radiation environment in low Earth orbit, validate body transport model and correlate organ level dose to skin dose. Presented are the test results of the prototype unit. The spherical phantom will be flown on the ISS in 2004 year and Liulin-5 experiment is planned for 2005 year. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 34; 6; 1297-301
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  • 90
    Publication Date: 2011-08-24
    Description: Space flight results in the exposure of astronauts to a mixed field of radiation composed of energetic particles of varying energies, and biological indicators of space radiation exposure provides a better understanding of the associated long-term health risks. Current methods of biodosimetry have employed the use of cytogenetic analysis for biodosimetry, and more recently the advent of technological progression has led to advanced research in the use of genomic and proteomic expression profiling to simultaneously assess biomarkers of radiation exposure. We describe here the technical advantages of the Luminex(TM) 100 system relative to traditional methods and its potential as a tool to simultaneously profile multiple proteins induced by ionizing radiation. The development of such a bioassay would provide more relevant post-translational dynamics of stress response and will impart important implications in the advancement of space and other radiation contact monitoring. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 34; 6; 1362-7
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  • 91
    Publication Date: 2011-08-24
    Description: In cells irradiation by heavy ions has been hypothesized to produce microlesions, regions of local damage. In cell membranes this damage is thought to manifest itself in the form of holes. The primary evidence for microlesions comes from morphological studies of cell membranes, but this evidence is still controversial, especially since holes also have been observed in membranes of normal, nonirradiated, cells. However, it is possible that damage not associated with histologically discernable disruptions may still occur. In order to resolve this issue, we developed a system for detecting microlesions based on liposomes filled with fluorescent dye. We hypothesized that if microlesions form in these liposomes as the result of irradiation, then the entrapped dye will leak out into the surrounding medium in a measurable way. Polypropylene vials containing suspensions of vesicles composed of either dipalmitoyl phosphatidylcholine, or a combination of egg phosphatidylcholine and cholesterol were irradiated at the Brookhaven National Laboratory using 56Fe ions at 1 GeV/amu. In several cases we obtained a significant loss of the entrapped dye above the background level. Our results suggest that holes may form in liposomes as the result of heavy ion irradiation, and that these holes are large enough to allow leakage of cell internal contents that are at least as large as a 1 nm diameter calcein molecule. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
    Keywords: Life Sciences (General)
    Type: Advances in space research : the official journal of the Committee on Space Research (COSPAR); Volume 34; 6; 1373-7
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  • 92
    Publication Date: 2011-08-24
    Description: Radiation-induced chromosome translocations remain in peripheral blood cells over many years, and can potentially be used to measure retrospective doses or prolonged low-dose rate exposures. However, several recent studies have indicated that some individuals possess clones of cells with balanced chromosome abnormalities, which can result in an overestimation of damage and, therefore, influence the accuracy of dose calculations. We carefully examined the patterns of chromosome damage found in the blood lymphocytes of twelve astronauts, and also applied statistical methods to screen for the presence of potential clones. Cells with clonal aberrations were identified in three of the twelve individuals. These clonal cells were present in samples collected both before and after space flight, and yields are higher than previously reported for healthy individuals in this age range (40-52 years of age). The frequency of clonal damage appears to be even greater in chromosomes prematurely condensed in interphase, when compared with equivalent analysis in metaphase cells. The individuals with clonal aberrations were followed-up over several months and the yields of all clones decreased during this period. Since clonal aberrations may be associated with increased risk of tumorigenesis, it is important to accurately identify cells containing clonal rearrangements for risk assessment as well as biodosimetry. Copyright 2003 S. Karger AG, Basel.
    Keywords: Life Sciences (General)
    Type: Cytogenetic and genome research (ISSN 1424-8581); Volume 104; 1-4; 245-51
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  • 93
    Publication Date: 2011-08-24
    Description: Because of the variability of collagen crosslinks, their use as markers for bone resorption is often criticized. We hypothesized that the variability could be reduced by collecting urine for 24 hours (or longer) instead of using single voids, and by not normalizing to creatinine. Urine samples were collected from 22 healthy subjects during two or more 24-hour periods. Each 24-hour pool and each 2nd void of the day were analyzed for N-telopeptide (NTX), pyridinium (PYD), and deoxypyridinoline (DPD) crosslinks. Data were analyzed by using linear regression. For NTX, R2 for the two, 2nd-void samples (n = 38) was 0.55, whereas R2 for the two 24-hour pools was 0.51 or 0.52, expressed per day or per creatinine. For PYD and DPD, R2 for the 2nd-void samples was 0.26 and 0.18, R2 for the 24-hour pools expressed per day was 0.58 and 0.74, and R2 for the 24-hour pools expressed per creatinine was 0.65 and 0.76, respectively. Regression of the 2nd void and the corresponding 24-hour pool, expressed per day, yielded R2 = 0.19, 0.19, and 0.08, for NTX, PYD, and DPD, respectively (n = 76 each). For the 2nd-void sample and its corresponding 24-hour pool, expressed per creatinine, R2 = 0.24, 0.33, and 0.08, respectively. In a separate study, the coefficient of variation for NTX was reduced (P 〈 0.05) when data from more than one 24-hour collection were combined. Thus, the variability inherent in crosslink determinations can be reduced by collecting urine for longer periods. In research studies, the high variability of single-void collections, compounded by creatinine normalization, may alter or obscure findings.
    Keywords: Life Sciences (General)
    Type: Calcified tissue international (ISSN 0171-967X); Volume 74; 4; 336-41
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  • 94
    Publication Date: 2011-08-24
    Description: Air passenger miles will likely double by year 2020. The altered and restrictive environment in an airliner cabin can influence haematological homeostasis in passengers and crew. Flight-related deep venous thromboemboli (DVT) have been associated with at least 577 deaths on 42 of 120 airlines from 1977 to 1984 (25 deaths/million departures), whereas many such cases go unreported. However, there are four major factors that could influence formation of possible flight-induced DVT: sleeping accommodations (via sitting immobilisation); travellers' medical history (via tissue injury); cabin environmental factors (via lower partial pressure of oxygen and lower relative humidity); and the more encompassing chair-rest deconditioning (C-RD) syndrome. There is ample evidence that recent injury and surgery (especially in deconditioned hospitalised patients) facilitate thrombophlebitis and formation of DVT that may be exacerbated by the immobilisation of prolonged air travel.In the healthy flying population, immobilisation factors associated with prolonged (〉5 hours) C-RD such as total body dehydration, hypovolaemia and increased blood viscosity, and reduced venous blood flow (pooling) in the legs may facilitate formation of DVT. However, data from at least four case-controlled epidemiological studies did not confirm a direct causative relationship between air travel and DVT, but factors such as a history of vascular thromboemboli, venous insufficiency, chronic heart failure, obesity, immobile standing position, more than three pregnancies, infectious disease, long-distance travel, muscular trauma and violent physical effort were significantly more frequent in DVT patients than in controls. Thus, there is no clear, direct evidence yet that prolonged sitting in airliner seats, or prolonged experimental chair-rest or bed-rest deconditioning treatments cause DVT in healthy people.
    Keywords: Life Sciences (General)
    Type: Sports medicine (Auckland, N.Z.) (ISSN 0112-1642); Volume 34; 11; 705-25
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  • 95
    Publication Date: 2011-08-24
    Description: Temperature, pressure, and time have been thought to control the smectite-to-illite (S-I) reaction, an important diagenetic process used for petroleum exploration. We demonstrated that microorganisms can promote the S-I reaction by dissolving smectite through reduction of structural Fe(III) at room temperature and 1 atmosphere within 14 days. This reaction typically requires conditions of 300 degrees to 350 degrees C, 100 megapascals, and 4 to 5 months in the absence of microbial activity. These results challenge the conventional concept of the S-I reaction and of reaction kinetic models.
    Keywords: Life Sciences (General)
    Type: Science (ISSN 0036-8075); Volume 303; 5659; 830-2
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  • 96
    Publication Date: 2011-08-24
    Description: The role of two binocular cues to motion in depth-changing disparity (CD) and interocular velocity difference (IOVD)- was investigated by measuring stereomotion speed discrimination and static disparity discrimination performance (stereoacuity). Speed discrimination thresholds were assessed both for random dot stereograms (RDS), and for their temporally uncorrelated equivalents, dynamic random dot stereograms (DRDS), at relative disparity pedestals of -19, 0, and +19 arcmin. While RDS stimuli contain both CD and IOVD cues, DRDS stimuli carry only CD information. On average, thresholds were a factor of 1.7 higher for DRDS than for RDS stimuli with no clear effect of relative disparity pedestal. Results were similar for approaching and receding targets. Variations in stimulus duration had no significant effect on thresholds, and there was no observed correlation between stimulus displacement and perceived speed, confirming that subjects responded to stimulus speed in each condition. Stereoacuity was equally good for our RDS and DRDS stimuli, showing that the difference in stereomotion speed discrimination performance for these stimuli was not due to any difference in the precision of the disparity cue. In addition, when we altered stereomotion stimulus trajectory by independently manipulating the speeds and directions of its monocular half-images, perceived stereomotion speed remained accurate. This finding is inconsistent with response strategies based on properties of either monocular half-image motion, or any ad hoc combination of the monocular speeds. We conclude that although subjects are able to discriminate stereomotion speed reliably on the basis of CD information alone, IOVD provides a precise additional cue to stereomotion speed perception.
    Keywords: Life Sciences (General)
    Type: Journal of vision (Charlottesville, Va.); Volume 4; 12; 1061-79
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  • 97
    Publication Date: 2011-08-24
    Description: To investigate effects of low dose heavy particle radiation to CNS system, we adopted mouse neonatal brain cells in culture being exposed to heavy ions by HIMAC at NIRS and NSRL at BNL. The applied dose varied from 0.05 Gy up to 2.0 Gy. The subsequent biological effects were evaluated by an induction of apoptosis and neuron survival focusing on the dependencies of the animal strains, SCID, B6, B6C3F1, C3H, used for brain cell culture, SCID was the most sensitive and C3H the least sensitive to particle radiation as evaluated by 10% apoptotic criterion. The LET dependency was compared with using SCID and B6 cells exposing to different ions (H, C, Ne, Si, Ar, and Fe). Although no detectable LET dependency was observed in the high LET (55-200 keV/micrometers) and low dose (〈0.5 Gy) regions. The survivability profiles of the neurons were different in the mouse strains and ions. In this report, a result of memory and learning function to adult mice after whole-body and brain local irradiation at carbon ion and iron ion.
    Keywords: Life Sciences (General)
    Type: Uchu seibutsu kagaku (ISSN 0914-9201); Volume 18; 3; 114-5
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  • 98
    Publication Date: 2011-08-24
    Description: Measurements of chromosome aberrations in peripheral blood lymphocytes are currently the most sensitive and reliable indicator of radiation exposure that can be used for biological dosimetry. This technique has been implemented recently to study radiation exposures incurred by astronauts during space flight, where a significant proportion of the dose is delivered by high-LET particle exposure. Traditional methods for the assessing of cytogenetic damage in mitotic cells collected at one time point after exposure may not be suitable for measuring high-LET radiation effects due to the drastic cell cycle perturbations and interphase cell death induced by this type of exposure. In this manuscript we review the recent advances in methodology used to study high-LET induced cytogenetic effects and evaluate the use of chemically-induced Premature Chromosome Condensation (PCC) as an alternative to metaphase analysis. Published data on the cytogenetic effects of in vitro exposures of high-LET radiation is reviewed, along with biodosimetry results from astronauts after short or long space missions.
    Keywords: Life Sciences (General)
    Type: Uchu seibutsu kagaku (ISSN 0914-9201); Volume 18; 4; 216-23
    Format: text
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  • 99
    Publication Date: 2011-08-24
    Description: We examined the apparent dissociation of perceived length and perceived position with respect to the Muller-Lyer (M-L) illusion. With the traditional (two-chevron) figure, participants made accurate open-loop pointing responses at the endpoints of the shaft, despite the presence of a strong length illusion. This apparently non-Euclidean outcome replicated that of Mack, Heuer, Villardi, and Chambers (1985) and Gillam and Chambers (1985) and contradicts any theory of the M-L illusion in which mislocalization of shaft endpoints plays a role. However, when one of the chevrons was removed, a constant pointing error occurred in the predicted direction, as well as a strong length illusion. Thus, with one-chevron stimuli, perceived length and location were no longer completely dissociated. We speculated that the presence of two opposing chevrons suppresses the mislocalizing effects of a single chevron, especially for figures with relatively short shafts.
    Keywords: Life Sciences (General)
    Type: Perception & psychophysics (ISSN 0031-5117); Volume 66; 7; 1095-104
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  • 100
    Publication Date: 2011-08-24
    Description: The National Aeronautics and Space Administration (NASA) has been conducting controlled environment research with potatoes (Solanum tuberosum L.) in recirculating nutrient film technique (NFT)-hydroponic systems as a human life support component during long-duration spaceflight. Standard nutrient solution management approaches include constant pH regulation with nitric acid (HNO3) and daily adjustment of electrical conductivity (EC) equivalent to half-strength modified Hoagland's solution, where nitrate (NO3-) is the sole nitrogen (N) source. Although tuber yields have been excellent with such an approach, N use efficiency indices are expected to be low relative to tuber biomass production. Furthermore, the high amount of N used in NFT-hydroponics, typically results in high inedible biomass, which conflicts with the need to minimize system mass, volume, and expenditure of resources for long-duration missions. More effective strategies of N fertilization need to be developed to more closely match N supply with demand of the crop. Hence, the primary objective of this study was to identify the optimal N management regime and plant N requirement to achieve high yields and to avoid inefficient use of N and excess inedible biomass production. In separate 84-day cropping experiments, three N management protocols were tested. Treatments which decreased NO3(-)-N supply indirectly through lowering nutrient solution EC (Expt. I), or disabling pH control, and/or supplying NH4(+)-N (Expt. III) did not significantly benefit tuber yield, but did influence N use efficiency indices. When supplied with an external 7.5 mM NO3(-)-N for the first 42 days after planting (DAP), lowered to 1.0 mM NO3(-)-N during the final 42 days (Expt. II), plants were able to achieve yields on par with plants which received constant 7.5 mM NO3(-)-N (control). By abruptly decreasing N supply at tuber initiation in Expt. II, less N was taken up and accumulated by plants compared to those which received high constant N (control). However, proportionately more plant accumulated N was used (N use efficiency) to produce tuber biomass when N supply was abruptly lowered at tuber initiation in Expt. II. Hence, a hydroponic nutrient solution N management system may be modified to elicit greater plant N-use while maintaining overall high tuber yield as opposed to achieving high tuber yields through excess N supply and shoot growth.
    Keywords: Life Sciences (General)
    Type: Journal of the American Society for Horticultural Science. American Society for Horticultural Science (ISSN 0003-1062); Volume 129; 1; 134-40
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