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  • 1
    Publication Date: 2010-10-15
    Description: Eukaryotes and archaea use a protease called the proteasome that has an integral role in maintaining cellular function through the selective degradation of proteins. Proteolysis occurs in a barrel-shaped 20S core particle, which in Thermoplasma acidophilum is built from four stacked homoheptameric rings of subunits, alpha and beta, arranged alpha(7)beta(7)beta(7)alpha(7) (ref. 5). These rings form three interconnected cavities, including a pair of antechambers (formed by alpha(7)beta(7)) through which substrates are passed before degradation and a catalytic chamber (beta(7)beta(7)) where the peptide-bond hydrolysis reaction occurs. Although it is clear that substrates must be unfolded to enter through narrow, gated passageways (13 A in diameter) located on the alpha-rings, the structural and dynamical properties of substrates inside the proteasome antechamber remain unclear. Confinement in the antechamber might be expected to promote folding and thus impede proteolysis. Here we investigate the folding, stability and dynamics of three small protein substrates in the antechamber by methyl transverse-relaxation-optimized NMR spectroscopy. We show that these substrates interact actively with the antechamber walls and have drastically altered kinetic and equilibrium properties that maintain them in unstructured states so as to be accessible for hydrolysis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ruschak, Amy M -- Religa, Tomasz L -- Breuer, Sarah -- Witt, Susanne -- Kay, Lewis E -- Canadian Institutes of Health Research/Canada -- England -- Nature. 2010 Oct 14;467(7317):868-71. doi: 10.1038/nature09444.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20944750" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Hydrolysis ; Kinetics ; Magnetic Resonance Spectroscopy ; Models, Molecular ; Molecular Sequence Data ; Proteasome Endopeptidase Complex/*chemistry/*metabolism ; Protein Folding ; *Protein Processing, Post-Translational ; Protein Stability ; Protein Subunits/chemistry/metabolism ; *Protein Unfolding ; Thermodynamics ; Thermoplasma/enzymology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2012-04-21
    Description: Protein-folding intermediates have been implicated in amyloid fibril formation involved in neurodegenerative disorders. However, the structural mechanisms by which intermediates initiate fibrillar aggregation have remained largely elusive. To gain insight, we used relaxation dispersion nuclear magnetic resonance spectroscopy to determine the structure of a low-populated, on-pathway folding intermediate of the A39V/N53P/V55L (A, Ala; V, Val; N, Asn; P, Pro; L, Leu) Fyn SH3 domain. The carboxyl terminus remains disordered in this intermediate, thereby exposing the aggregation-prone amino-terminal beta strand. Accordingly, mutants lacking the carboxyl terminus and thus mimicking the intermediate fail to safeguard the folding route and spontaneously form fibrillar aggregates. The structure provides a detailed characterization of the non-native interactions stabilizing an aggregation-prone intermediate under native conditions and insight into how such an intermediate can derail folding and initiate fibrillation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Neudecker, Philipp -- Robustelli, Paul -- Cavalli, Andrea -- Walsh, Patrick -- Lundstrom, Patrik -- Zarrine-Afsar, Arash -- Sharpe, Simon -- Vendruscolo, Michele -- Kay, Lewis E -- 089703/Wellcome Trust/United Kingdom -- Canadian Institutes of Health Research/Canada -- New York, N.Y. -- Science. 2012 Apr 20;336(6079):362-6. doi: 10.1126/science.1214203.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22517863" target="_blank"〉PubMed〈/a〉
    Keywords: Amyloid/*chemistry ; Animals ; Chickens ; Hydrogen Bonding ; Models, Molecular ; Molecular Dynamics Simulation ; Mutant Proteins/chemistry ; Nuclear Magnetic Resonance, Biomolecular ; Protein Conformation ; *Protein Folding ; Protein Structure, Secondary ; Proto-Oncogene Proteins c-fyn/*chemistry/genetics ; Thermodynamics ; *src Homology Domains
    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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  • 3
    Publication Date: 2005-07-05
    Description: Cell signaling that culminates in posttranslational modifications directs protein activity. Here we report how multiple Ca2+-dependent phosphorylation sites within the transcription activator Ets-1 act additively to produce graded DNA binding affinity. Nuclear magnetic resonance spectroscopic analyses show that phosphorylation shifts Ets-1 from a dynamic conformation poised to bind DNA to a well-folded inhibited state. These phosphates lie in an unstructured flexible region that functions as the allosteric effector of autoinhibition. Variable phosphorylation thus serves as a "rheostat" for cell signaling to fine-tune transcription at the level of DNA binding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pufall, Miles A -- Lee, Gregory M -- Nelson, Mary L -- Kang, Hyun-Seo -- Velyvis, Algirdas -- Kay, Lewis E -- McIntosh, Lawrence P -- Graves, Barbara J -- GM08537/GM/NIGMS NIH HHS/ -- P01-CA24014/CA/NCI NIH HHS/ -- R01 GM38663/GM/NIGMS NIH HHS/ -- T32-CA93247/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2005 Jul 1;309(5731):142-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112-5550, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15994560" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Amino Acid Sequence ; Amino Acid Substitution ; Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; Calcium-Calmodulin-Dependent Protein Kinases/metabolism ; DNA/*metabolism ; Hydrophobic and Hydrophilic Interactions ; Mice ; Models, Molecular ; Molecular Sequence Data ; Mutation ; Nuclear Magnetic Resonance, Biomolecular ; Phosphorylation ; Protein Binding ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Proto-Oncogene Protein c-ets-1 ; Proto-Oncogene Proteins/*chemistry/genetics/*metabolism ; Proto-Oncogene Proteins c-ets ; Signal Transduction ; Transcription Factors/*chemistry/genetics/*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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  • 4
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2006-04-15
    Description: There is growing evidence that structural flexibility plays a central role in the function of protein molecules. Many of the experimental data come from nuclear magnetic resonance (NMR) spectroscopy, a technique that allows internal motions to be probed with exquisite time and spatial resolution. Recent methodological advancements in NMR have extended our ability to characterize protein dynamics and promise to shed new light on the mechanisms by which these molecules function. Here, we present a brief overview of some of the new methods, together with applications that illustrate the level of detail at which protein motions can now be observed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mittermaier, Anthony -- Kay, Lewis E -- New York, N.Y. -- Science. 2006 Apr 14;312(5771):224-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, McGill University, Montreal, Quebec H3A 2K6, Canada. anthony.mittermaier@mcgill.ca.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16614210" target="_blank"〉PubMed〈/a〉
    Keywords: Bacterial Proteins/chemistry ; Chemistry, Physical ; Kinetics ; Motion ; *Nuclear Magnetic Resonance, Biomolecular/methods ; Physicochemical Phenomena ; *Protein Conformation ; *Protein Folding ; Proteins/*chemistry ; Proto-Oncogene Proteins c-fyn/chemistry ; Temperature ; Thermodynamics ; src Homology Domains
    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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  • 5
    Publication Date: 2010-09-11
    Description: Proteins can sample conformational states that are critical for function but are seldom detected directly because of their low occupancies and short lifetimes. In this work, we used chemical shifts and bond-vector orientation constraints obtained from nuclear magnetic resonance relaxation dispersion spectroscopy, in concert with a chemical shift-based method for structure elucidation, to determine an atomic-resolution structure of an "invisible" folding intermediate of a small protein module: the FF domain. The structure reveals non-native elements preventing formation of the native conformation in the carboxyl-terminal part of the protein. This is consistent with the kinetics of folding in which a well-structured intermediate forms rapidly and then rearranges slowly to the native state. The approach introduces a general strategy for structure determination of low-populated and transiently formed protein states.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Korzhnev, Dmitry M -- Religa, Tomasz L -- Banachewicz, Wiktor -- Fersht, Alan R -- Kay, Lewis E -- MC_U105484373/Medical Research Council/United Kingdom -- Canadian Institutes of Health Research/Canada -- New York, N.Y. -- Science. 2010 Sep 10;329(5997):1312-6. doi: 10.1126/science.1191723.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics, the University of Toronto, Toronto, Ontario M5S 1A8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20829478" target="_blank"〉PubMed〈/a〉
    Keywords: Carrier Proteins/*chemistry ; Computational Biology ; Kinetics ; Models, Molecular ; Nuclear Magnetic Resonance, Biomolecular ; Protein Conformation ; *Protein Folding ; Protein Structure, Secondary ; *Protein Structure, Tertiary ; Software ; 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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  • 6
    Publication Date: 2010-04-03
    Description: The proteasome catalyzes the majority of protein degradation in the cell and plays an integral role in cellular homeostasis. Control over proteolysis by the 20S core-particle (CP) proteasome is achieved by gated access of substrate; thus, an understanding of the molecular mechanism by which these gates regulate substrate entry is critical. We used methyl-transverse relaxation optimized nuclear magnetic resonance spectroscopy to show that the amino-terminal residues that compose the gates of the alpha subunits of the Thermoplasma acidophilum proteasome are highly dynamic over a broad spectrum of time scales and that gating termini are in conformations that extend either well inside (closed gate) or outside (open gate) of the antechamber. Interconversion between these conformers on a time scale of seconds leads to a dynamic regulation of 20S CP proteolysis activity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Religa, Tomasz L -- Sprangers, Remco -- Kay, Lewis E -- Canadian Institutes of Health Research/Canada -- New York, N.Y. -- Science. 2010 Apr 2;328(5974):98-102. doi: 10.1126/science.1184991.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20360109" target="_blank"〉PubMed〈/a〉
    Keywords: Archaeal Proteins/*chemistry/genetics/*metabolism ; Electron Spin Resonance Spectroscopy ; Endopeptidases/*chemistry/genetics/*metabolism ; Models, Molecular ; Mutant Proteins/chemistry/metabolism ; Nuclear Magnetic Resonance, Biomolecular ; Protein Conformation ; Protein Structure, Quaternary ; Protein Subunits/chemistry/metabolism ; Spin Labels ; Thermoplasma/chemistry/*enzymology/genetics/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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