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  • 1
    Publication Date: 2002-05-11
    Description: The ABC transporters are ubiquitous membrane proteins that couple adenosine triphosphate (ATP) hydrolysis to the translocation of diverse substrates across cell membranes. Clinically relevant examples are associated with cystic fibrosis and with multidrug resistance of pathogenic bacteria and cancer cells. Here, we report the crystal structure at 3.2 angstrom resolution of the Escherichia coli BtuCD protein, an ABC transporter mediating vitamin B12 uptake. The two ATP-binding cassettes (BtuD) are in close contact with each other, as are the two membrane-spanning subunits (BtuC); this arrangement is distinct from that observed for the E. coli lipid flippase MsbA. The BtuC subunits provide 20 transmembrane helices grouped around a translocation pathway that is closed to the cytoplasm by a gate region whereas the dimer arrangement of the BtuD subunits resembles the ATP-bound form of the Rad50 DNA repair enzyme. A prominent cytoplasmic loop of BtuC forms the contact region with the ATP-binding cassette and appears to represent a conserved motif among the ABC transporters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Locher, Kaspar P -- Lee, Allen T -- Rees, Douglas C -- New York, N.Y. -- Science. 2002 May 10;296(5570):1091-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, Mail Code 147-75CH, California Institute of Technology, Pasadena, CA 91125, USA. locher@caltech.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12004122" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/*chemistry/metabolism ; Adenosine Triphosphate/metabolism ; Amino Acid Motifs ; Amino Acid Sequence ; Binding Sites ; Biological Transport ; Cell Membrane/chemistry ; Crystallization ; Crystallography, X-Ray ; Dimerization ; Escherichia coli/*chemistry ; Escherichia coli Proteins/*chemistry/metabolism ; Hydrolysis ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Folding ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Protein Subunits ; Vitamin B 12/*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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  • 2
    Publication Date: 2015-08-13
    Description: The flipping of membrane-embedded lipids containing large, polar head groups is slow and energetically unfavourable, and is therefore catalysed by flippases, the mechanisms of which are unknown. A prominent example of a flipping reaction is the translocation of lipid-linked oligosaccharides that serve as donors in N-linked protein glycosylation. In Campylobacter jejuni, this process is catalysed by the ABC transporter PglK. Here we present a mechanism of PglK-catalysed lipid-linked oligosaccharide flipping based on crystal structures in distinct states, a newly devised in vitro flipping assay, and in vivo studies. PglK can adopt inward- and outward-facing conformations in vitro, but only outward-facing states are required for flipping. While the pyrophosphate-oligosaccharide head group of lipid-linked oligosaccharides enters the translocation cavity and interacts with positively charged side chains, the lipidic polyprenyl tail binds and activates the transporter but remains exposed to the lipid bilayer during the reaction. The proposed mechanism is distinct from the classical alternating-access model applied to other transporters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Perez, Camilo -- Gerber, Sabina -- Boilevin, Jeremy -- Bucher, Monika -- Darbre, Tamis -- Aebi, Markus -- Reymond, Jean-Louis -- Locher, Kaspar P -- England -- Nature. 2015 Aug 27;524(7566):433-8. doi: 10.1038/nature14953. Epub 2015 Aug 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland. ; Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland. ; Institute of Microbiology, ETH Zurich, CH-8093 Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26266984" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/*chemistry/*metabolism ; Adenosine Triphosphatases/chemistry/metabolism ; Adenosine Triphosphate/metabolism ; *Biocatalysis ; Campylobacter jejuni/cytology/*enzymology/metabolism ; Crystallography, X-Ray ; Hydrolysis ; Lipid Bilayers/metabolism ; Lipopolysaccharides/*metabolism ; Models, Molecular ; Protein Conformation ; Structure-Activity Relationship
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2007-08-04
    Description: BtuCD is an adenosine triphosphate-binding cassette (ABC) transporter that translocates vitamin B12 from the periplasmic binding protein BtuF into the cytoplasm of Escherichia coli. The 2.6 angstrom crystal structure of a complex BtuCD-F reveals substantial conformational changes as compared with the previously reported structures of BtuCD and BtuF. The lobes of BtuF are spread apart, and B12 is displaced from the binding pocket. The transmembrane BtuC subunits reveal two distinct conformations, and the translocation pathway is closed to both sides of the membrane. Electron paramagnetic resonance spectra of spin-labeled cysteine mutants reconstituted in proteoliposomes are consistent with the conformation of BtuCD-F that was observed in the crystal structure. A comparison with BtuCD and the homologous HI1470/71 protein suggests that the structure of BtuCD-F may reflect a posttranslocation intermediate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hvorup, Rikki N -- Goetz, Birke A -- Niederer, Martina -- Hollenstein, Kaspar -- Perozo, Eduardo -- Locher, Kaspar P -- New York, N.Y. -- Science. 2007 Sep 7;317(5843):1387-90. Epub 2007 Aug 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Biology and Biophysics, ETH Zurich, HPK D14.3, 8093 Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17673622" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/*chemistry ; Amino Acid Sequence ; Crystallography, X-Ray ; Electron Spin Resonance Spectroscopy ; Escherichia coli ; Escherichia coli Proteins/*chemistry ; Models, Molecular ; Molecular Sequence Data ; Periplasmic Binding Proteins/*chemistry ; Protein Binding ; Protein Conformation ; Recombinant Fusion Proteins/chemistry
    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
    Publication Date: 2006-12-13
    Description: The crystal structure of a putative metal-chelate-type adenosine triphosphate (ATP)-binding cassette (ABC) transporter encoded by genes HI1470 and HI1471 of Haemophilus influenzae has been solved at 2.4 angstrom resolution. The permeation pathway exhibits an inward-facing conformation, in contrast to the outward-facing state previously observed for the homologous vitamin B12 importer BtuCD. Although the structures of both HI1470/1 and BtuCD have been solved in nucleotide-free states, the pairs of ABC subunits in these two structures differ by a translational shift in the plane of the membrane that coincides with a repositioning of the membrane-spanning subunits. The differences observed between these ABC transporters involve relatively modest rearrangements and may serve as structural models for inward- and outward-facing conformations relevant to the alternating access mechanism of substrate translocation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pinkett, H W -- Lee, A T -- Lum, P -- Locher, K P -- Rees, D C -- GM45162/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2007 Jan 19;315(5810):373-7. Epub 2006 Dec 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, MC 114-96, California Institute of Technology (Caltech), Pasadena, CA 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17158291" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/*chemistry ; Bacterial Proteins/*chemistry ; Catalytic Domain ; Crystallography, X-Ray ; Dimerization ; Haemophilus influenzae/*chemistry ; Metals/metabolism ; Models, Molecular ; Protein Conformation ; Protein Folding ; Protein Structure, Quaternary ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Protein Subunits/chemistry
    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
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 2003-08-02
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Locher, Kaspar P -- Bass, Randal B -- Rees, Douglas C -- New York, N.Y. -- Science. 2003 Aug 1;301(5633):603-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Molekularbiologie und Biophysik, Eidgenossische Technische Hochschule Zurich, Zurich CH-8093, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12893929" target="_blank"〉PubMed〈/a〉
    Keywords: Binding Sites ; Biological Transport ; Cell Membrane/enzymology ; Crystallography, X-Ray ; Escherichia coli/chemistry/enzymology ; Escherichia coli Proteins/*chemistry/metabolism ; Glycerophosphates/metabolism ; Lactose/metabolism ; Membrane Transport Proteins/*chemistry/metabolism ; Models, Molecular ; *Monosaccharide Transport Proteins ; Phosphates/metabolism ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; *Symporters
    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: 2011-06-17
    Description: Asparagine-linked glycosylation is a post-translational modification of proteins containing the conserved sequence motif Asn-X-Ser/Thr. The attachment of oligosaccharides is implicated in diverse processes such as protein folding and quality control, organism development or host-pathogen interactions. The reaction is catalysed by oligosaccharyltransferase (OST), a membrane protein complex located in the endoplasmic reticulum. The central, catalytic enzyme of OST is the STT3 subunit, which has homologues in bacteria and archaea. Here we report the X-ray structure of a bacterial OST, the PglB protein of Campylobacter lari, in complex with an acceptor peptide. The structure defines the fold of STT3 proteins and provides insight into glycosylation sequon recognition and amide nitrogen activation, both of which are prerequisites for the formation of the N-glycosidic linkage. We also identified and validated catalytically important, acidic amino acid residues. Our results provide the molecular basis for understanding the mechanism of N-linked glycosylation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lizak, Christian -- Gerber, Sabina -- Numao, Shin -- Aebi, Markus -- Locher, Kaspar P -- England -- Nature. 2011 Jun 15;474(7351):350-5. doi: 10.1038/nature10151.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Microbiology, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21677752" target="_blank"〉PubMed〈/a〉
    Keywords: Amides/metabolism ; Amino Acid Motifs ; Asparagine/chemistry/genetics/metabolism ; Campylobacter lari/*enzymology ; Catalytic Domain ; Crystallography, X-Ray ; Glycosylation ; Hexosyltransferases/*chemistry/genetics/metabolism ; Membrane Proteins/*chemistry/genetics/metabolism ; Models, Molecular ; Nitrogen/metabolism ; Protein Binding ; Protein Structure, Tertiary ; Structure-Activity Relationship ; Substrate Specificity
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 2012-09-25
    Description: The ATP-binding cassette (ABC) transporter BtuCD mediates the uptake of vitamin B(12) across the inner membrane of Escherichia coli. Previous structures have shown the conformations of apo states, but the transport mechanism has remained unclear. Here we report the 3.5 A crystal structure of the transporter-binding protein complex BtuCD-BtuF (BtuCD-F) trapped in an beta-gamma-imidoadenosine 5'-phosphate (AMP-PNP)-bound intermediate state. Although the ABC domains (BtuD subunits) form the expected closed sandwich dimer, the membrane-spanning BtuC subunits adopt a new conformation, with the central translocation pathway sealed by a previously unrecognized cytoplasmic gate. A fully enclosed cavity is thus formed approximately halfway across the membrane. It is large enough to accommodate a vitamin B(12) molecule, and radioligand trapping showed that liposome-reconstituted BtuCD-F indeed contains bound B(12) in the presence of AMP-PNP. In combination with engineered disulphide crosslinking and functional assays, our data suggest an unexpected peristaltic transport mechanism that is distinct from those observed in other ABC transporters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Korkhov, Vladimir M -- Mireku, Samantha A -- Locher, Kaspar P -- England -- Nature. 2012 Oct 18;490(7420):367-72. doi: 10.1038/nature11442. Epub 2012 Sep 23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23000901" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/*chemistry/genetics/metabolism ; Adenosine Triphosphatases/chemistry/metabolism ; Adenosine Triphosphate/metabolism ; Adenylyl Imidodiphosphate/chemistry/*metabolism ; Amino Acid Sequence ; Crystallography, X-Ray ; Cytoplasm/metabolism ; Disulfides/chemistry/metabolism ; Escherichia coli/*chemistry/genetics ; Escherichia coli Proteins/*chemistry/genetics/metabolism ; Magnesium/metabolism ; Models, Biological ; Models, Molecular ; Mutant Proteins/chemistry/genetics/metabolism ; Mutation ; Periplasmic Binding Proteins/*chemistry/genetics/metabolism ; Protein Binding ; Protein Conformation ; Protein Subunits/chemistry/genetics/metabolism ; Structure-Activity Relationship ; Vitamin B 12/chemistry/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 2008-05-31
    Description: Transport across cellular membranes is an essential process that is catalyzed by diverse membrane transport proteins. The turnover rates of certain transporters are inhibited by their substrates in a process termed trans-inhibition, whose structural basis is poorly understood. We present the crystal structure of a molybdate/tungstate ABC transporter (ModBC) from Methanosarcina acetivorans in a trans-inhibited state. The regulatory domains of the nucleotide-binding subunits are in close contact and provide two oxyanion binding pockets at the shared interface. By specifically binding to these pockets, molybdate or tungstate prevent adenosine triphosphatase activity and lock the transporter in an inward-facing conformation, with the catalytic motifs of the nucleotide-binding domains separated. This allosteric effect prevents the transporter from switching between the inward-facing and the outward-facing states, thus interfering with the alternating access and release mechanism.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gerber, Sabina -- Comellas-Bigler, Mireia -- Goetz, Birke A -- Locher, Kaspar P -- New York, N.Y. -- Science. 2008 Jul 11;321(5886):246-50. doi: 10.1126/science.1156213. Epub 2008 May 29.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Molecular Biology and Biophysics, ETH Zurich, HPK D14.3, 8093 Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18511655" target="_blank"〉PubMed〈/a〉
    Keywords: ATP-Binding Cassette Transporters/*antagonists & inhibitors/*chemistry/metabolism ; Adenosine Triphosphatases/metabolism ; Adenosine Triphosphate/metabolism ; Amino Acid Motifs ; Amino Acid Sequence ; Archaeal Proteins/antagonists & inhibitors/*chemistry/metabolism ; Binding Sites ; Catalytic Domain ; Crystallography, X-Ray ; Methanosarcina/*chemistry ; Models, Molecular ; Molecular Sequence Data ; Molybdenum/*metabolism ; Protein Conformation ; Protein Folding ; Protein Structure, Tertiary ; Tungsten Compounds/*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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  • 9
    Publication Date: 2002-12-10
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 10
    Publication Date: 2019
    Description: 〈p〉ABCB1, also known as P-glycoprotein, actively extrudes xenobiotic compounds across the plasma membrane of diverse cells, which contributes to cellular drug resistance and interferes with therapeutic drug delivery. We determined the 3.5-angstrom cryo–electron microscopy structure of substrate-bound human ABCB1 reconstituted in lipidic nanodiscs, revealing a single molecule of the chemotherapeutic compound paclitaxel (Taxol) bound in a central, occluded pocket. A second structure of inhibited, human-mouse chimeric ABCB1 revealed two molecules of zosuquidar occupying the same drug-binding pocket. Minor structural differences between substrate- and inhibitor-bound ABCB1 sites are amplified toward the nucleotide-binding domains (NBDs), revealing how the plasticity of the drug-binding site controls the dynamics of the adenosine triphosphate–hydrolyzing NBDs. Ordered cholesterol and phospholipid molecules suggest how the membrane modulates the conformational changes associated with drug binding and transport.〈/p〉
    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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