1401
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Swayampakula M, Baral PK, Aguzzi A, Kav NNV, James MNG. The crystal structure of an octapeptide repeat of the prion protein in complex with a Fab fragment of the POM2 antibody. Protein Sci 2013; 22:893-903. [PMID: 23629842 DOI: 10.1002/pro.2270] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 11/09/2022]
Abstract
Prion diseases are progressive, infectious neurodegenerative disorders caused primarily by the misfolding of the cellular prion protein (PrP(c)) into an insoluble, protease-resistant, aggregated isoform termed PrP(sc). In native conditions, PrP(c) has a structured C-terminal domain and a highly flexible N-terminal domain. A part of this N-terminal domain consists of 4-5 repeats of an unusual glycine-rich, eight amino acids long peptide known as the octapeptide repeat (OR) domain. In this article, we successfully report the first crystal structure of an OR of PrP(c) bound to the Fab fragment of the POM2 antibody. The structure was solved at a resolution of 2.3 Å by molecular replacement. Although several studies have previously predicted a β-turn-like structure of the unbound ORs, our structure shows an extended conformation of the OR when bound to a molecule of the POM2 Fab indicating that the bound Fab disrupts any putative native β turn conformation of the ORs. Encouraging results from several recent studies have shown that administering small molecule ligands or antibodies targeting the OR domain of PrP result in arresting the progress of peripheral prion infections both in ex vivo and in in vivo models. This makes the structural study of the interactions of POM2 Fab with the OR domain very important as it would help us to design smaller and tighter binding OR ligands.
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Affiliation(s)
- Mridula Swayampakula
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
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1402
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Production of a human neutralizing monoclonal antibody and its crystal structure in complex with ectodomain 3 of the interleukin-13 receptor α1. Biochem J 2013; 451:165-75. [PMID: 23384096 DOI: 10.1042/bj20121819] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Gene deletion studies in mice have revealed critical roles for IL (interleukin)-4 and -13 in asthma development, with the latter controlling lung airways resistance and mucus secretion. We have now developed human neutralizing monoclonal antibodies against human IL-13Rα1 (IL-13 receptor α1) subunit that prevent activation of the receptor complex by both IL-4 and IL-13. We describe the crystal structures of the Fab fragment of antibody 10G5H6 alone and in complex with D3 (ectodomain 3) of IL-13Rα1. Although the structure showed significant domain swapping within a D3 dimer, we showed that Arg(230), Phe(233), Tyr(250), Gln(252) and Leu(293) in each D3 monomer and Ser(32), Asn(102) and Trp(103) in 10G5H6 Fab are the key interacting residues at the interface of the 10G5H6 Fab-D3 complex. One of the most striking contacts is the insertion of the ligand-contacting residue Leu(293) of D3 into a deep pocket on the surface of 10G5H6 Fab, and this appears to be a central determinant of the high binding affinity and neutralizing activity of the antibody.
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1403
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Chang YM, Chen CKM, Ko TP, Chang-Chien MW, Wang AHJ. Structural analysis of the antibiotic-recognition mechanism of MarR proteins. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1138-49. [PMID: 23695258 DOI: 10.1107/s0907444913007117] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 03/14/2013] [Indexed: 11/11/2022]
Abstract
Staphylococci cause a wide range of diseases in humans and animals, and the proteins of the multiple antibiotic-resistance repressor (MarR) family in staphylococci function as regulators of protein expression and confer resistance to multiple antibiotics. Diverse mechanisms such as biofilm formation, drug transport, drug modification etc. are associated with this resistance. In this study, crystal structures of the Staphylococcus aureus MarR homologue SAR2349 and its complex with salicylate and the aminoglycoside antibiotic kanamycin have been determined. The structure of SAR2349 shows for the first time that a MarR protein can interact directly with different classes of ligands simultaneously and highlights the importance and versatility of regulatory systems in bacterial antibiotic resistance. The three-dimensional structures of TcaR from S. epidermidis in complexes with chloramphenicol and with the aminoglycoside antibiotic streptomycin were also investigated. The crystal structures of the TcaR and SAR2349 complexes illustrate a general antibiotic-regulated resistance mechanism that may extend to other MarR proteins. To reveal the regulatory mechanism of the MarR proteins, the protein structures of this family were further compared and three possible mechanisms of regulation are proposed. These results are of general interest because they reveal a remarkably broad spectrum of ligand-binding modes of the multifunctional MarR proteins. This finding provides further understanding of antimicrobial resistance mechanisms in pathogens and strategies to develop new therapies against pathogens.
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Affiliation(s)
- Yu Ming Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
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1404
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Bjelić S, Wieser M, Frey D, Stirnimann CU, Chance MR, Jaussi R, Steinmetz MO, Kammerer RA. Structural basis for the oligomerization-state switch from a dimer to a trimer of an engineered cortexillin-1 coiled-coil variant. PLoS One 2013; 8:e63370. [PMID: 23691037 PMCID: PMC3653964 DOI: 10.1371/journal.pone.0063370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 03/30/2013] [Indexed: 11/19/2022] Open
Abstract
Coiled coils are well suited to drive subunit oligomerization and are widely used in applications ranging from basic research to medicine. The optimization of these applications requires a detailed understanding of the molecular determinants that control of coiled-coil formation. Although many of these determinants have been identified and characterized in great detail, a puzzling observation is that their presence does not necessarily correlate with the oligomerization state of a given coiled-coil structure. Thus, other determinants must play a key role. To address this issue, we recently investigated the unrelated coiled-coil domains from GCN4, ATF1 and cortexillin-1 as model systems. We found that well-known trimer-specific oligomerization-state determinants, such as the distribution of isoleucine residues at heptad-repeat core positions or the trimerization motif Arg-h-x-x-h-Glu (where h = hydrophobic amino acid; x = any amino acid), switch the peptide's topology from a dimer to a trimer only when inserted into the trigger sequence, a site indispensable for coiled-coil formation. Because high-resolution structural information could not be obtained for the full-length, three-stranded cortexillin-1 coiled coil, we here report the detailed biophysical and structural characterization of a shorter variant spanning the trigger sequence using circular dichroism, anatytical ultracentrifugation and x-ray crystallography. We show that the peptide forms a stable α-helical trimer in solution. We further determined the crystal structure of an optimised variant at a resolution of 1.65 Å, revealing that the peptide folds into a parallel, three-stranded coiled coil. The two complemented R-IxxIE trimerization motifs and the additional hydrophobic core isoleucine residue adopt the conformations seen in other extensively characterized parallel, three-stranded coiled coils. These findings not only confirm the structural basis for the switch in oligomerization state from a dimer to a trimer observed for the full-length cortexillin-1 coiled-coil domain, but also provide further evidence for a general link between oligomerization-state specificity and trigger-sequence function.
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Affiliation(s)
- Saša Bjelić
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
- Center for Proteomics & Bioinformatics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Mara Wieser
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
| | - Daniel Frey
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
| | | | - Mark R. Chance
- Center for Proteomics & Bioinformatics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Rolf Jaussi
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
| | - Michel O. Steinmetz
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
| | - Richard A. Kammerer
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen, Switzerland
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1405
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Rambo RP, Tainer JA. Accurate assessment of mass, models and resolution by small-angle scattering. Nature 2013; 496:477-81. [PMID: 23619693 PMCID: PMC3714217 DOI: 10.1038/nature12070] [Citation(s) in RCA: 582] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 03/13/2013] [Indexed: 01/08/2023]
Abstract
Modern small angle scattering (SAS) experiments with X-rays or neutrons provide a comprehensive, resolution-limited observation of the thermodynamic state. However, methods for evaluating mass and validating SAS based models and resolution have been inadequate. Here, we define the volume-of-correlation, Vc: a SAS invariant derived from the scattered intensities that is specific to the structural state of the particle, yet independent of concentration and the requirements of a compact, folded particle. We show Vc defines a ratio, Qr, that determines the molecular mass of proteins or RNA ranging from 10 to 1,000 kDa. Furthermore, we propose a statistically robust method for assessing model-data agreements (X2free) akin to cross-validation. Our approach prevents over-fitting of the SAS data and can be used with a newly defined metric, Rsas, for quantitative evaluation of resolution. Together, these metrics (Vc, Qr, X2free, and Rsas) provide analytical tools for unbiased and accurate macromolecular structural characterizations in solution.
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Affiliation(s)
- Robert P Rambo
- Life Sciences Division, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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1406
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Krug M, Lee SJ, Boos W, Diederichs K, Welte W. The three-dimensional structure of TrmB, a transcriptional regulator of dual function in the hyperthermophilic archaeon Pyrococcus furiosus in complex with sucrose. Protein Sci 2013; 22:800-8. [PMID: 23576322 DOI: 10.1002/pro.2263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/06/2013] [Accepted: 03/06/2013] [Indexed: 01/02/2023]
Abstract
TrmB is a repressor that binds maltose, maltotriose, and sucrose, as well as other α-glucosides. It recognizes two different operator sequences controlling the TM (Trehalose/Maltose) and the MD (Maltodextrin) operon encoding the respective ABC transporters and sugar-degrading enzymes. Binding of maltose to TrmB abrogates repression of the TM operon but maintains the repression of the MD operon. On the other hand, binding of sucrose abrogates repression of the MD operon but maintains repression of the TM operon. The three-dimensional structure of TrmB in complex with sucrose was solved and refined to a resolution of 3.0 Å. The structure shows the N-terminal DNA binding domain containing a winged-helix-turn-helix (wHTH) domain followed by an amphipathic helix with a coiled-coil motif. The latter promotes dimerization and places the symmetry mates of the putative recognition helix in the wHTH motif about 30 Å apart suggesting a canonical binding to two successive major grooves of duplex palindromic DNA. This suggests that the structure resembles the conformation of TrmB recognizing the pseudopalindromic TM promoter but not the conformation recognizing the nonpalindromic MD promoter.
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Affiliation(s)
- Michael Krug
- Department of Biology, University of Konstanz, Konstanz, Germany
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1407
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Structural and energetic basis of folded-protein transport by the FimD usher. Nature 2013; 496:243-6. [PMID: 23579681 PMCID: PMC3673227 DOI: 10.1038/nature12007] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 02/14/2013] [Indexed: 11/09/2022]
Abstract
Type 1 pili, produced by uropathogenic Escherichia coli, are multisubunit fibres crucial in recognition of and adhesion to host tissues. During pilus biogenesis, subunits are recruited to an outer membrane assembly platform, the FimD usher, which catalyses their polymerization and mediates pilus secretion. The recent determination of the crystal structure of an initiation complex provided insight into the initiation step of pilus biogenesis resulting in pore activation, but very little is known about the elongation steps that follow. Here, to address this question, we determine the structure of an elongation complex in which the tip complex assembly composed of FimC, FimF, FimG and FimH passes through FimD. This structure demonstrates the conformational changes required to prevent backsliding of the nascent pilus through the FimD pore and also reveals unexpected properties of the usher pore. We show that the circular binding interface between the pore lumen and the folded substrate participates in transport by defining a low-energy pathway along which the nascent pilus polymer is guided during secretion.
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1408
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Kern J, Alonso-Mori R, Tran R, Hattne J, Gildea RJ, Echols N, Glöckner C, Hellmich J, Laksmono H, Sierra RG, Lassalle-Kaiser B, Koroidov S, Lampe A, Han G, Gul S, DiFiore D, Milathianaki D, Fry AR, Miahnahri A, Schafer DW, Messerschmidt M, Seibert MM, Koglin JE, Sokaras D, Weng TC, Sellberg J, Latimer MJ, Grosse-Kunstleve RW, Zwart PH, White WE, Glatzel P, Adams PD, Bogan MJ, Williams GJ, Boutet S, Messinger J, Zouni A, Sauter NK, Yachandra VK, Bergmann U, Yano J. Simultaneous femtosecond X-ray spectroscopy and diffraction of photosystem II at room temperature. Science 2013; 340:491-5. [PMID: 23413188 PMCID: PMC3732582 DOI: 10.1126/science.1234273] [Citation(s) in RCA: 303] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Intense femtosecond x-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous x-ray diffraction (XRD) and x-ray emission spectroscopy (XES) of microcrystals of photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD-XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation-sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies.
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Affiliation(s)
- Jan Kern
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Rosalie Tran
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Johan Hattne
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Richard J. Gildea
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Nathaniel Echols
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Carina Glöckner
- Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany
| | - Julia Hellmich
- Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany
| | - Hartawan Laksmono
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Raymond G. Sierra
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Sergey Koroidov
- Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, Umeå, Sweden
| | - Alyssa Lampe
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Guangye Han
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Sheraz Gul
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Dörte DiFiore
- Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany
| | | | - Alan R. Fry
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Alan Miahnahri
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Donald W. Schafer
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - M. Marvin Seibert
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jason E. Koglin
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Tsu-Chien Weng
- SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jonas Sellberg
- SSRL, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, AlbaNova, Stockholm University, S-106 91 Stockholm, Sweden
| | | | | | - Petrus H. Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - William E. White
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Pieter Glatzel
- European Synchrotron Radiation Facility, F-38043 Grenoble Cedex, France
| | - Paul D. Adams
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Michael J. Bogan
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Garth J. Williams
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Sébastien Boutet
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Johannes Messinger
- Institutionen för Kemi, Kemiskt Biologiskt Centrum, Umeå Universitet, Umeå, Sweden
| | - Athina Zouni
- Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität, D-10623 Berlin, Germany
| | - Nicholas K. Sauter
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Vittal K. Yachandra
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Uwe Bergmann
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Junko Yano
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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1409
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Nowak E, Potrzebowski W, Konarev PV, Rausch JW, Bona MK, Svergun DI, Bujnicki JM, Le Grice SFJ, Nowotny M. Structural analysis of monomeric retroviral reverse transcriptase in complex with an RNA/DNA hybrid. Nucleic Acids Res 2013; 41:3874-87. [PMID: 23382176 PMCID: PMC3616737 DOI: 10.1093/nar/gkt053] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/11/2013] [Accepted: 01/11/2013] [Indexed: 11/19/2022] Open
Abstract
A key step in proliferation of retroviruses is the conversion of their RNA genome to double-stranded DNA, a process catalysed by multifunctional reverse transcriptases (RTs). Dimeric and monomeric RTs have been described, the latter exemplified by the enzyme of Moloney murine leukaemia virus. However, structural information is lacking that describes the substrate binding mechanism for a monomeric RT. We report here the first crystal structure of a complex between an RNA/DNA hybrid substrate and polymerase-connection fragment of the single-subunit RT from xenotropic murine leukaemia virus-related virus, a close relative of Moloney murine leukaemia virus. A comparison with p66/p51 human immunodeficiency virus-1 RT shows that substrate binding around the polymerase active site is conserved but differs in the thumb and connection subdomains. Small-angle X-ray scattering was used to model full-length xenotropic murine leukaemia virus-related virus RT, demonstrating that its mobile RNase H domain becomes ordered in the presence of a substrate-a key difference between monomeric and dimeric RTs.
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Affiliation(s)
- Elżbieta Nowak
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Wojciech Potrzebowski
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Petr V. Konarev
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Jason W. Rausch
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Marion K. Bona
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Dmitri I. Svergun
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Janusz M. Bujnicki
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Stuart F. J. Le Grice
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, 4 Trojdena Street, 02-109 Warsaw, Poland, European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany, RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory, Frederick, MD 21702, USA and Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
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1410
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Pedersen BP, Kumar H, Waight AB, Risenmay AJ, Roe-Zurz Z, Chau BH, Schlessinger A, Bonomi M, Harries W, Sali A, Johri AK, Stroud RM. Crystal structure of a eukaryotic phosphate transporter. Nature 2013; 496:533-6. [PMID: 23542591 PMCID: PMC3678552 DOI: 10.1038/nature12042] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/25/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Bjørn P Pedersen
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, USA
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1411
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Czabotar PE, Westphal D, Dewson G, Ma S, Hockings C, Fairlie WD, Lee EF, Yao S, Robin AY, Smith BJ, Huang DCS, Kluck RM, Adams JM, Colman PM. Bax crystal structures reveal how BH3 domains activate Bax and nucleate its oligomerization to induce apoptosis. Cell 2013; 152:519-31. [PMID: 23374347 DOI: 10.1016/j.cell.2012.12.031] [Citation(s) in RCA: 422] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/11/2012] [Accepted: 12/10/2012] [Indexed: 02/06/2023]
Abstract
In stressed cells, apoptosis ensues when Bcl-2 family members Bax or Bak oligomerize and permeabilize the mitochondrial outer membrane. Certain BH3-only relatives can directly activate them to mediate this pivotal, poorly understood step. To clarify the conformational changes that induce Bax oligomerization, we determined crystal structures of BaxΔC21 treated with detergents and BH3 peptides. The peptides bound the Bax canonical surface groove but, unlike their complexes with prosurvival relatives, dissociated Bax into two domains. The structures define the sequence signature of activator BH3 domains and reveal how they can activate Bax via its groove by favoring release of its BH3 domain. Furthermore, Bax helices α2-α5 alone adopted a symmetric homodimer structure, supporting the proposal that two Bax molecules insert their BH3 domain into each other's surface groove to nucleate oligomerization. A planar lipophilic surface on this homodimer may engage the membrane. Our results thus define critical Bax transitions toward apoptosis.
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Affiliation(s)
- Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia.
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1412
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Volkov A, Khoshnevis S, Neumann P, Herrfurth C, Wohlwend D, Ficner R, Feussner I. Crystal structure analysis of a fatty acid double-bond hydratase from Lactobacillus acidophilus. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:648-57. [PMID: 23519674 DOI: 10.1107/s0907444913000991] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 01/10/2013] [Indexed: 11/10/2022]
Abstract
Bacteria have evolved mechanisms for the hydrogenation of unsaturated fatty acids. Hydroxy fatty acid formation may be the first step in such a process; however, knowledge of the structural and mechanistic aspects of this reaction is scarce. Recently, myosin cross-reactive antigen was shown to be a bacterial FAD-containing hydratase which acts on the 9Z and 12Z double bonds of C16 and C18 non-esterified fatty acids, with the formation of 10-hydroxy and 10,13-dihydroxy fatty acids. These fatty acid hydratases form a large protein family which is conserved across Gram-positive and Gram-negative bacteria with no sequence similarity to any known protein apart from the FAD-binding motif. In order to shed light on the substrate recognition and the mechanism of the hydratase reaction, the crystal structure of the hydratase from Lactobacillus acidophilus (LAH) was determined by single-wavelength anomalous dispersion. Crystal structures of apo LAH and of LAH with bound linoleic acid were refined at resolutions of 2.3 and 1.8 Å, respectively. LAH is a homodimer; each protomer consists of four intricately connected domains. Three of them form the FAD-binding and substrate-binding sites and reveal structural similarity to three domains of several flavin-dependent enzymes, including amine oxidoreductases. The additional fourth domain of LAH is located at the C-terminus and consists of three α-helices. It covers the entrance to the hydrophobic substrate channel leading from the protein surface to the active site. In the presence of linoleic acid, the fourth domain of one protomer undergoes conformational changes and opens the entrance to the substrate-binding channel of the other protomer of the LAH homodimer. The linoleic acid molecule is bound at the entrance to the substrate channel, suggesting movement of the lid domain triggered by substrate recognition.
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Affiliation(s)
- Anton Volkov
- Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, Göttingen, Germany
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1413
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Kershaw NJ, Murphy JM, Liau NPD, Varghese LN, Laktyushin A, Whitlock EL, Lucet IS, Nicola NA, Babon JJ. SOCS3 binds specific receptor-JAK complexes to control cytokine signaling by direct kinase inhibition. Nat Struct Mol Biol 2013; 20:469-76. [PMID: 23454976 PMCID: PMC3618588 DOI: 10.1038/nsmb.2519] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/11/2013] [Indexed: 12/03/2022]
Abstract
The inhibitory protein SOCS3 plays a key role in the immune and hematopoietic systems by regulating signaling induced by specific cytokines. SOCS3 functions by inhibiting the catalytic activity of Janus Kinases (JAKs) that initiate signaling within the cell. We determined the crystal structure of a ternary complex between murine SOCS3, JAK2 (kinase domain) and a fragment of the IL-6 receptor β-chain. The structure shows that SOCS3 binds JAK2 and receptor simultaneously, using two opposing surfaces. Whilst the phosphotyrosine-binding groove on the SOCS3 SH2 domain is occupied by receptor, JAK2 binds in a phospho-independent manner to a non-canonical surface. The kinase inhibitory region of SOCS3 occludes the substrate-binding groove on JAK2 and biochemical studies show it blocks substrate association. These studies reveal that SOCS3 targets specific JAK-cytokine receptor pairs and explains the mechanism and specificity of SOCS action.
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Affiliation(s)
- Nadia J Kershaw
- Department of Structural Biology, Walter and Eliza Hall Institute, Parkville, Australia
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1414
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Leysen S, Vanderkelen L, Weeks SD, Michiels CW, Strelkov SV. Structural basis of bacterial defense against g-type lysozyme-based innate immunity. Cell Mol Life Sci 2013; 70:1113-22. [PMID: 23086131 PMCID: PMC11113182 DOI: 10.1007/s00018-012-1184-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/21/2012] [Accepted: 09/27/2012] [Indexed: 10/27/2022]
Abstract
Gram-negative bacteria can produce specific proteinaceous inhibitors to defend themselves against the lytic action of host lysozymes. So far, four different lysozyme inhibitor families have been identified. Here, we report the crystal structure of the Escherichia coli periplasmic lysozyme inhibitor of g-type lysozyme (PliG-Ec) in complex with Atlantic salmon g-type lysozyme (SalG) at a resolution of 0.95 Å, which is exceptionally high for a complex of two proteins. The structure reveals for the first time the mechanism of g-type lysozyme inhibition by the PliG family. The latter contains two specific conserved regions that are essential for its inhibitory activity. The inhibitory complex formation is based on a double 'key-lock' mechanism. The first key-lock element is formed by the insertion of two conserved PliG regions into the active site of the lysozyme. The second element is defined by a distinct pocket of PliG accommodating a lysozyme loop. Computational analysis indicates that this pocket represents a suitable site for small molecule binding, which opens an avenue for the development of novel antibacterial agents that suppress the inhibitory activity of PliG.
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Affiliation(s)
- S. Leysen
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - L. Vanderkelen
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - S. D. Weeks
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - C. W. Michiels
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - S. V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
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1415
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Menting JG, Whittaker J, Margetts MB, Whittaker LJ, Kong GKW, Smith BJ, Watson CJ, Záková L, Kletvíková E, Jiráček J, Chan SJ, Steiner DF, Dodson GG, Brzozowski AM, Weiss MA, Ward CW, Lawrence MC. How insulin engages its primary binding site on the insulin receptor. Nature 2013; 493:241-5. [PMID: 23302862 DOI: 10.1038/nature11781] [Citation(s) in RCA: 287] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 11/12/2012] [Indexed: 12/24/2022]
Abstract
Insulin receptor signalling has a central role in mammalian biology, regulating cellular metabolism, growth, division, differentiation and survival. Insulin resistance contributes to the pathogenesis of type 2 diabetes mellitus and the onset of Alzheimer's disease; aberrant signalling occurs in diverse cancers, exacerbated by cross-talk with the homologous type 1 insulin-like growth factor receptor (IGF1R). Despite more than three decades of investigation, the three-dimensional structure of the insulin-insulin receptor complex has proved elusive, confounded by the complexity of producing the receptor protein. Here we present the first view, to our knowledge, of the interaction of insulin with its primary binding site on the insulin receptor, on the basis of four crystal structures of insulin bound to truncated insulin receptor constructs. The direct interaction of insulin with the first leucine-rich-repeat domain (L1) of insulin receptor is seen to be sparse, the hormone instead engaging the insulin receptor carboxy-terminal α-chain (αCT) segment, which is itself remodelled on the face of L1 upon insulin binding. Contact between insulin and L1 is restricted to insulin B-chain residues. The αCT segment displaces the B-chain C-terminal β-strand away from the hormone core, revealing the mechanism of a long-proposed conformational switch in insulin upon receptor engagement. This mode of hormone-receptor recognition is novel within the broader family of receptor tyrosine kinases. We support these findings by photo-crosslinking data that place the suggested interactions into the context of the holoreceptor and by isothermal titration calorimetry data that dissect the hormone-insulin receptor interface. Together, our findings provide an explanation for a wealth of biochemical data from the insulin receptor and IGF1R systems relevant to the design of therapeutic insulin analogues.
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Affiliation(s)
- John G Menting
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
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1416
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Kim JH, Resende R, Wennekes T, Chen HM, Bance N, Buchini S, Watts AG, Pilling P, Streltsov VA, Petric M, Liggins R, Barrett S, McKimm-Breschkin JL, Niikura M, Withers SG. Mechanism-based covalent neuraminidase inhibitors with broad-spectrum influenza antiviral activity. Science 2013; 340:71-5. [PMID: 23429702 DOI: 10.1126/science.1232552] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Influenza antiviral agents play important roles in modulating disease severity and in controlling pandemics while vaccines are prepared, but the development of resistance to agents like the commonly used neuraminidase inhibitor oseltamivir may limit their future utility. We report here on a new class of specific, mechanism-based anti-influenza drugs that function through the formation of a stabilized covalent intermediate in the influenza neuraminidase enzyme, and we confirm this mode of action with structural and mechanistic studies. These compounds function in cell-based assays and in animal models, with efficacies comparable to that of the neuraminidase inhibitor zanamivir and with broad-spectrum activity against drug-resistant strains in vitro. The similarity of their structure to that of the natural substrate and their mechanism-based design make these attractive antiviral candidates.
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Affiliation(s)
- Jin-Hyo Kim
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
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1417
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Tan TC, Spadiut O, Wongnate T, Sucharitakul J, Krondorfer I, Sygmund C, Haltrich D, Chaiyen P, Peterbauer CK, Divne C. The 1.6 Å crystal structure of pyranose dehydrogenase from Agaricus meleagris rationalizes substrate specificity and reveals a flavin intermediate. PLoS One 2013; 8:e53567. [PMID: 23326459 PMCID: PMC3541233 DOI: 10.1371/journal.pone.0053567] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 11/29/2012] [Indexed: 11/18/2022] Open
Abstract
Pyranose dehydrogenases (PDHs) are extracellular flavin-dependent oxidoreductases secreted by litter-decomposing fungi with a role in natural recycling of plant matter. All major monosaccharides in lignocellulose are oxidized by PDH at comparable yields and efficiencies. Oxidation takes place as single-oxidation or sequential double-oxidation reactions of the carbohydrates, resulting in sugar derivatives oxidized primarily at C2, C3 or C2/3 with the concomitant reduction of the flavin. A suitable electron acceptor then reoxidizes the reduced flavin. Whereas oxygen is a poor electron acceptor for PDH, several alternative acceptors, e.g., quinone compounds, naturally present during lignocellulose degradation, can be used. We have determined the 1.6-Å crystal structure of PDH from Agaricus meleagris. Interestingly, the flavin ring in PDH is modified by a covalent mono- or di-atomic species at the C(4a) position. Under normal conditions, PDH is not oxidized by oxygen; however, the related enzyme pyranose 2-oxidase (P2O) activates oxygen by a mechanism that proceeds via a covalent flavin C(4a)-hydroperoxide intermediate. Although the flavin C(4a) adduct is common in monooxygenases, it is unusual for flavoprotein oxidases, and it has been proposed that formation of the intermediate would be unfavorable in these oxidases. Thus, the flavin adduct in PDH not only shows that the adduct can be favorably accommodated in the active site, but also provides important details regarding the structural, spatial and physicochemical requirements for formation of this flavin intermediate in related oxidases. Extensive in silico modeling of carbohydrates in the PDH active site allowed us to rationalize the previously reported patterns of substrate specificity and regioselectivity. To evaluate the regioselectivity of D-glucose oxidation, reduction experiments were performed using fluorinated glucose. PDH was rapidly reduced by 3-fluorinated glucose, which has the C2 position accessible for oxidation, whereas 2-fluorinated glucose performed poorly (C3 accessible), indicating that the glucose C2 position is the primary site of attack.
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Affiliation(s)
- Tien Chye Tan
- School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Oliver Spadiut
- School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Thanyaporn Wongnate
- Department of Biochemistry and Center of Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Iris Krondorfer
- Food Biotechnology Laboratory, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christoph Sygmund
- Food Biotechnology Laboratory, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Dietmar Haltrich
- Food Biotechnology Laboratory, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Pimchai Chaiyen
- Department of Biochemistry and Center of Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Clemens K. Peterbauer
- Food Biotechnology Laboratory, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christina Divne
- School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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1418
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Prota AE, Bargsten K, Zurwerra D, Field JJ, Díaz JF, Altmann KH, Steinmetz MO. Molecular Mechanism of Action of Microtubule-Stabilizing Anticancer Agents. Science 2013; 339:587-90. [DOI: 10.1126/science.1230582] [Citation(s) in RCA: 358] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microtubule-stabilizing agents (MSAs) are efficacious chemotherapeutic drugs widely used for the treatment of cancer. Despite the importance of MSAs for medical applications and basic research, their molecular mechanisms of action on tubulin and microtubules remain elusive. We determined high-resolution crystal structures of αβ-tubulin in complex with two unrelated MSAs, zampanolide and epothilone A. Both compounds were bound to the taxane pocket of β-tubulin and used their respective side chains to induce structuring of the M-loop into a short helix. Because the M-loop establishes lateral tubulin contacts in microtubules, these findings explain how taxane-site MSAs promote microtubule assembly and stability. Further, our results offer fundamental structural insights into the control mechanisms of microtubule dynamics.
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1419
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Sharma P, Yamini S, Dube D, Singh A, Mal G, Pandey N, Sinha M, Singh AK, Dey S, Kaur P, Mitra DK, Sharma S, Singh TP. Structural basis of the binding of fatty acids to peptidoglycan recognition protein, PGRP-S through second binding site. Arch Biochem Biophys 2013; 529:1-10. [PMID: 23149273 DOI: 10.1016/j.abb.2012.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 10/31/2012] [Accepted: 11/03/2012] [Indexed: 11/24/2022]
Abstract
Short peptidoglycan recognition protein (PGRP-S) is a member of the mammalian innate immune system. PGRP-S from Camelus dromedarius (CPGRP-S) has been shown to bind to lipopolysaccharide (LPS), lipoteichoic acid (LTA) and peptidoglycan (PGN). Its structure consists of four molecules A, B, C and D with ligand binding clefts situated at A-B and C-D contacts. It has been shown that LPS, LTA and PGN bind to CPGRP-S at C-D contact. The cleft at the A-B contact indicated features that suggested a possible binding of fatty acids including mycolic acid of Mycobacterium tuberculosis. Therefore, binding studies of CPGRP-S were carried out with fatty acids, butyric acid, lauric acid, myristic acid, stearic acid and mycolic acid which showed affinities in the range of 10(-5) to 10(-8) M. Structure determinations of the complexes of CPGRP-S with above fatty acids showed that they bound to CPGRP-S in the cleft at the A-B contact. The flow cytometric studies showed that mycolic acid induced the production of pro-inflammatory cytokines, TNF-α and IFN-γ by CD3+ T cells. The concentrations of cytokines increased considerably with increasing concentrations of mycolic acid. However, their levels decreased substantially on adding CPGRP-S.
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Affiliation(s)
- Pradeep Sharma
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
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1420
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Volbeda A, Darnault C, Parkin A, Sargent F, Armstrong FA, Fontecilla-Camps JC. Crystal structure of the O(2)-tolerant membrane-bound hydrogenase 1 from Escherichia coli in complex with its cognate cytochrome b. Structure 2012; 21:184-190. [PMID: 23260654 DOI: 10.1016/j.str.2012.11.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/10/2012] [Accepted: 11/15/2012] [Indexed: 10/27/2022]
Abstract
We report the 3.3 Å resolution structure of dimeric membrane-bound O(2)-tolerant hydrogenase 1 from Escherichia coli in a 2:1 complex with its physiological partner, cytochrome b. From the short distance between distal [Fe(4)S(4)] clusters, we predict rapid transfer of H(2)-derived electrons between hydrogenase heterodimers. Thus, under low O(2) levels, a functional active site in one heterodimer can reductively reactivate its O(2)-exposed counterpart in the other. Hydrogenase 1 is maximally expressed during fermentation, when electron acceptors are scarce. These conditions are achieved in the lower part of the host's intestinal tract when E. coli is soon to be excreted and undergo an anaerobic-to-aerobic metabolic transition. The apparent paradox of having an O(2)-tolerant hydrogenase expressed under anoxia makes sense if the enzyme functions to keep intracellular O(2) levels low by reducing it to water, protecting O(2)-sensitive enzymes during the transition. Cytochrome b's main role may be anchoring the hydrogenase to the membrane.
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Affiliation(s)
- Anne Volbeda
- Metalloproteins Unit, Institut de Biologie Structurale J.-P. Ebel CEA-CNRS-Université Joseph Fourier, UMR 5075, 41 rue Jules Horowitz, 38027 Grenoble, France
| | - Claudine Darnault
- Metalloproteins Unit, Institut de Biologie Structurale J.-P. Ebel CEA-CNRS-Université Joseph Fourier, UMR 5075, 41 rue Jules Horowitz, 38027 Grenoble, France
| | - Alison Parkin
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Frank Sargent
- College of Life Sciences, University of Dundee, Dow Street, Dundee DD15EH, Scotland, UK
| | - Fraser A Armstrong
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Juan C Fontecilla-Camps
- Metalloproteins Unit, Institut de Biologie Structurale J.-P. Ebel CEA-CNRS-Université Joseph Fourier, UMR 5075, 41 rue Jules Horowitz, 38027 Grenoble, France.
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1421
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Kim MI, Shin I, Cho S, Lee J, Rhee S. Structural and functional insights into (S)-ureidoglycolate dehydrogenase, a metabolic branch point enzyme in nitrogen utilization. PLoS One 2012; 7:e52066. [PMID: 23284870 PMCID: PMC3527362 DOI: 10.1371/journal.pone.0052066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 11/09/2012] [Indexed: 12/17/2022] Open
Abstract
Nitrogen metabolism is one of essential processes in living organisms. The catabolic pathways of nitrogenous compounds play a pivotal role in the storage and recovery of nitrogen. In Escherichia coli, two different, interconnecting metabolic routes drive nitrogen utilization through purine degradation metabolites. The enzyme (S)-ureidoglycolate dehydrogenase (AllD), which is a member of l-sulfolactate dehydrogenase-like family, converts (S)-ureidoglycolate, a key intermediate in the purine degradation pathway, to oxalurate in an NAD(P)-dependent manner. Therefore, AllD is a metabolic branch-point enzyme for nitrogen metabolism in E. coli. Here, we report crystal structures of AllD in its apo form, in a binary complex with NADH cofactor, and in a ternary complex with NADH and glyoxylate, a possible spontaneous degradation product of oxalurate. Structural analyses revealed that NADH in an extended conformation is bound to an NADH-binding fold with three distinct domains that differ from those of the canonical NADH-binding fold. We also characterized ligand-induced structural changes, as well as the binding mode of glyoxylate, in the active site near the NADH nicotinamide ring. Based on structural and kinetic analyses, we concluded that AllD selectively utilizes NAD+ as a cofactor, and further propose that His116 acts as a general catalytic base and that a hydride transfer is possible on the B-face of the nicotinamide ring of the cofactor. Other residues conserved in the active sites of this novel l-sulfolactate dehydrogenase-like family also play essential roles in catalysis.
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Affiliation(s)
- Myung-Il Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Inchul Shin
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Suhee Cho
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Jeehyun Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Sangkee Rhee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
- Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
- * E-mail:
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1422
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HLA-DO acts as a substrate mimic to inhibit HLA-DM by a competitive mechanism. Nat Struct Mol Biol 2012; 20:90-8. [PMID: 23222639 PMCID: PMC3537886 DOI: 10.1038/nsmb.2460] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 10/25/2012] [Indexed: 12/03/2022]
Abstract
MHCII proteins bind peptide antigens in endosomal compartments of antigen-presenting cells. The non-classical MHCII protein HLA-DM chaperones peptide-free MHCII against inactivation and catalyzes peptide exchange on loaded MHCII. Another non-classical MHCII protein, HLA-DO, binds HLA-DM and influences the repertoire of peptides presented by MHCII proteins. However, the mechanism by which HLA-DO functions is unclear. Here we use x-ray crystallography, enzyme kinetics and mutagenesis approaches to investigate human HLA-DO structure and function. In complex with HLA-DM, HLA-DO adopts a classical MHCII structure, with alterations near the alpha subunit 310 helix. HLA-DO binds to HLA-DM at the same sites implicated in MHCII interaction, and kinetic analysis demonstrates that HLA-DO acts as a competitive inhibitor. These results show that HLA-DO inhibits HLA-DM function by acting as a substrate mimic and place constraints on possible functional roles for HLA-DO in antigen presentation.
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1423
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Reiss K, Stencel JE, Liu Y, Blaum BS, Reiter DM, Feizi T, Dermody TS, Stehle T. The GM2 glycan serves as a functional coreceptor for serotype 1 reovirus. PLoS Pathog 2012; 8:e1003078. [PMID: 23236285 PMCID: PMC3516570 DOI: 10.1371/journal.ppat.1003078] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 10/23/2012] [Indexed: 01/13/2023] Open
Abstract
Viral attachment to target cells is the first step in infection and also serves as a determinant of tropism. Like many viruses, mammalian reoviruses bind with low affinity to cell-surface carbohydrate receptors to initiate the infectious process. Reoviruses disseminate with serotype-specific tropism in the host, which may be explained by differential glycan utilization. Although α2,3-linked sialylated oligosaccharides serve as carbohydrate receptors for type 3 reoviruses, neither a specific glycan bound by any reovirus serotype nor the function of glycan binding in type 1 reovirus infection was known. We have identified the oligosaccharide portion of ganglioside GM2 (the GM2 glycan) as a receptor for the attachment protein σ1 of reovirus strain type 1 Lang (T1L) using glycan array screening. The interaction of T1L σ1 with GM2 in solution was confirmed using NMR spectroscopy. We established that GM2 glycan engagement is required for optimal infection of mouse embryonic fibroblasts (MEFs) by T1L. Preincubation with GM2 specifically inhibited type 1 but not type 3 reovirus infection of MEFs. To provide a structural basis for these observations, we defined the mode of receptor recognition by determining the crystal structure of T1L σ1 in complex with the GM2 glycan. GM2 binds in a shallow groove in the globular head domain of T1L σ1. Both terminal sugar moieties of the GM2 glycan, N-acetylneuraminic acid and N-acetylgalactosamine, form contacts with the protein, providing an explanation for the observed specificity for GM2. Viruses with mutations in the glycan-binding domain display diminished hemagglutination capacity, a property dependent on glycan binding, and reduced capacity to infect MEFs. Our results define a novel mode of virus-glycan engagement and provide a mechanistic explanation for the serotype-dependent differences in glycan utilization by reovirus.
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MESH Headings
- Animals
- Cricetinae
- Embryo, Mammalian/metabolism
- Embryo, Mammalian/pathology
- Embryo, Mammalian/virology
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Fibroblasts/virology
- Gangliosidoses, GM2/genetics
- Gangliosidoses, GM2/metabolism
- L Cells
- Mice
- Mutation
- Orthoreovirus, Mammalian/genetics
- Orthoreovirus, Mammalian/metabolism
- Protein Structure, Tertiary
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Reoviridae Infections/genetics
- Reoviridae Infections/metabolism
- Reoviridae Infections/pathology
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Kerstin Reiss
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jennifer E. Stencel
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Yan Liu
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Bärbel S. Blaum
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Dirk M. Reiter
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Ten Feizi
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Terence S. Dermody
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
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1424
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Rudolph MG, del Toro Duany Y, Jungblut SP, Ganguly A, Klostermeier D. Crystal structures of Thermotoga maritima reverse gyrase: inferences for the mechanism of positive DNA supercoiling. Nucleic Acids Res 2012. [PMID: 23209025 PMCID: PMC3553957 DOI: 10.1093/nar/gks1073] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Reverse gyrase is an ATP-dependent topoisomerase that is unique to hyperthermophilic archaea and eubacteria. The only reverse gyrase structure determined to date has revealed the arrangement of the N-terminal helicase domain and the C-terminal topoisomerase domain that intimately cooperate to generate the unique function of positive DNA supercoiling. Although the structure has elicited hypotheses as to how supercoiling may be achieved, it lacks structural elements important for supercoiling and the molecular mechanism of positive supercoiling is still not clear. We present five structures of authentic Thermotoga maritima reverse gyrase that reveal a first view of two interacting zinc fingers that are crucial for positive DNA supercoiling. The so-called latch domain, which connects the helicase and the topoisomerase domains is required for their functional cooperation and presents a novel fold. Structural comparison defines mobile regions in parts of the helicase domain, including a helical insert and the latch that are likely important for DNA binding during catalysis. We show that the latch, the helical insert and the zinc fingers contribute to the binding of DNA to reverse gyrase and are uniquely placed within the reverse gyrase structure to bind and guide DNA during strand passage. A possible mechanism for positive supercoiling by reverse gyrases is presented.
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Affiliation(s)
- Markus G Rudolph
- pRED, Pharma Research and Early Development, Discovery Technologies, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
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1425
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Roberts A, Gill R, Hussey RJ, Mikolajek H, Erskine PT, Cooper JB, Wood SP, Chrystal EJT, Shoolingin-Jordan PM. Crystallization and preliminary X-ray characterization of the tetrapyrrole-biosynthetic enzyme porphobilinogen deaminase from Arabidopsis thaliana. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1491-3. [PMID: 23192030 PMCID: PMC3509971 DOI: 10.1107/s1744309112042212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 10/08/2012] [Indexed: 11/10/2022]
Abstract
The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step of the haem-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor which is covalently linked by a thioether bridge to an invariant cysteine residue. Since PBGD catalyses a reaction which is common to the biosynthesis of both haem and chlorophyll, structural studies of a plant PBGD enzyme offer great potential for the discovery of novel herbicides. Until recently, structural data have only been available for the Escherichia coli and human forms of the enzyme. Expression in E. coli of a codon-optimized gene for Arabidopsis thaliana PBGD has permitted for the first time the crystallization and preliminary X-ray analysis of the enzyme from a plant species at high resolution.
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Affiliation(s)
- A. Roberts
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, England
| | - R. Gill
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - R. J. Hussey
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, England
| | - H. Mikolajek
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, England
| | - P. T. Erskine
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - J. B. Cooper
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - S. P. Wood
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - E. J. T. Chrystal
- Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, England
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1426
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Cody V, Pace J, Nawar HF, King-Lyons N, Liang S, Connell TD, Hajishengallis G. Structure-activity correlations of variant forms of the B pentamer of Escherichia coli type II heat-labile enterotoxin LT-IIb with Toll-like receptor 2 binding. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1604-12. [PMID: 23151625 PMCID: PMC3498930 DOI: 10.1107/s0907444912038917] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 09/11/2012] [Indexed: 03/21/2023]
Abstract
The pentameric B subunit of the type II heat-labile enterotoxin of Escherichia coli (LT-IIb-B(5)) is a potent signaling molecule capable of modulating innate immune responses. It has previously been shown that LT-IIb-B(5), but not the LT-IIb-B(5) Ser74Asp variant [LT-IIb-B(5)(S74D)], activates Toll-like receptor (TLR2) signaling in macrophages. Consistent with this, the LT-IIb-B(5)(S74D) variant failed to bind TLR2, in contrast to LT-IIb-B(5) and the LT-IIb-B(5) Thr13Ile [LT-IIb-B(5)(T13I)] and LT-IIb-B(5) Ser74Ala [LT-IIb-B(5)(S74A)] variants, which displayed the highest binding activity to TLR2. Crystal structures of the Ser74Asp, Ser74Ala and Thr13Ile variants of LT-IIb-B(5) have been determined to 1.90, 1.40 and 1.90 Å resolution, respectively. The structural data for the Ser74Asp variant reveal that the carboxylate side chain points into the pore, thereby reducing the pore size compared with that of the wild-type or the Ser74Ala variant B pentamer. On the basis of these crystallographic data, the reduced TLR2-binding affinity of the LT-IIb-B(5)(S74D) variant may be the result of the pore of the pentamer being closed. On the other hand, the explanation for the enhanced TLR2-binding activity of the LT-IIb-B(5)(S74A) variant is more complex as its activity is greater than that of the wild-type B pentamer, which also has an open pore as the Ser74 side chain points away from the pore opening. Data for the LT-IIb-B(5)(T13I) variant show that four of the five variant side chains point to the outside surface of the pentamer and one residue points inside. These data are consistent with the lack of binding of the LT-IIb-B(5)(T13I) variant to GD1a ganglioside.
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Affiliation(s)
- Vivian Cody
- Structural Biology Department, Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA.
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1427
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Bunker RD, Bulloch EMM, Dickson JMJ, Loomes KM, Baker EN. Structure and function of human xylulokinase, an enzyme with important roles in carbohydrate metabolism. J Biol Chem 2012. [PMID: 23179721 DOI: 10.1074/jbc.m112.427997] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
D-Xylulokinase (XK; EC 2.7.1.17) catalyzes the ATP-dependent phosphorylation of d-xylulose (Xu) to produce xylulose 5-phosphate (Xu5P). In mammals, XK is the last enzyme in the glucuronate-xylulose pathway, active in the liver and kidneys, and is linked through its product Xu5P to the pentose-phosphate pathway. XK may play an important role in metabolic disease, given that Xu5P is a key regulator of glucose metabolism and lipogenesis. We have expressed the product of a putative human XK gene and identified it as the authentic human d-xylulokinase (hXK). NMR studies with a variety of sugars showed that hXK acts only on d-xylulose, and a coupled photometric assay established its key kinetic parameters as K(m)(Xu) = 24 ± 3 μm and k(cat) = 35 ± 5 s(-1). Crystal structures were determined for hXK, on its own and in complexes with Xu, ADP, and a fluorinated inhibitor. These reveal that hXK has a two-domain fold characteristic of the sugar kinase/hsp70/actin superfamily, with glycerol kinase as its closest relative. Xu binds to domain-I and ADP to domain-II, but in this open form of hXK they are 10 Å apart, implying that a large scale conformational change is required for catalysis. Xu binds in its linear keto-form, sandwiched between a Trp side chain and polar side chains that provide exquisite hydrogen bonding recognition. The hXK structure provides a basis for the design of specific inhibitors with which to probe its roles in sugar metabolism and metabolic disease.
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Affiliation(s)
- Richard D Bunker
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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1428
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Dong X, Mi LZ, Zhu J, Wang W, Hu P, Luo BH, Springer TA. α(V)β(3) integrin crystal structures and their functional implications. Biochemistry 2012; 51:8814-28. [PMID: 23106217 PMCID: PMC3495331 DOI: 10.1021/bi300734n] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many questions about the significance of structural features of integrin α(V)β(3) with respect to its mechanism of activation remain. We have determined and re-refined crystal structures of the α(V)β(3) ectodomain linked to C-terminal coiled coils (α(V)β(3)-AB) and four transmembrane (TM) residues in each subunit (α(V)β(3)-1TM), respectively. The α(V) and β(3) subunits with four and eight extracellular domains, respectively, are bent at knees between the integrin headpiece and lower legs, and the headpiece has the closed, low-affinity conformation. The structures differ in the occupancy of three metal-binding sites in the βI domain. Occupancy appears to be related to the pH of crystallization, rather than to the physiologic regulation of ligand binding at the central, metal ion-dependent adhesion site. No electron density was observed for TM residues and much of the α(V) linker. α(V)β(3)-AB and α(V)β(3)-1TM demonstrate flexibility in the linker between their extracellular and TM domains, rather than the previously proposed rigid linkage. A previously postulated interface between the α(V) and β(3) subunits at their knees was also not supported, because it lacks high-quality density, required rebuilding in α(V)β(3)-1TM, and differed markedly between α(V)β(3)-1TM and α(V)β(3)-AB. Together with the variation in domain-domain orientation within their bent ectodomains between α(V)β(3)-AB and α(V)β(3)-1TM, these findings are compatible with the requirement for large structural changes, such as extension at the knees and headpiece opening, in conveying activation signals between the extracellular ligand-binding site and the cytoplasm.
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Affiliation(s)
- Xianchi Dong
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - Li-Zhi Mi
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - Jianghai Zhu
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - Wei Wang
- Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803
| | - Ping Hu
- Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803
| | - Bing-Hao Luo
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
- Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803
| | - Timothy A. Springer
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
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1429
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Oyenarte I, Majtan T, Ereño J, Corral-Rodríguez MA, Kraus JP, Martínez-Cruz LA. Purification, crystallization and preliminary crystallographic analysis of human cystathionine β-synthase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1318-22. [PMID: 23143240 PMCID: PMC3515372 DOI: 10.1107/s1744309112037219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 08/29/2012] [Indexed: 06/01/2023]
Abstract
Human cystathionine β-synthase (CBS) is a pyridoxal-5'-phosphate-dependent hemeprotein, whose catalytic activity is regulated by S-adenosylmethionine. CBS catalyzes the β-replacement reaction of homocysteine (Hcy) with serine to yield cystathionine. CBS is a key regulator of plasma levels of the thrombogenic Hcy and deficiency in CBS is the single most common cause of homocystinuria, an inherited metabolic disorder of sulfur amino acids. The properties of CBS enzymes, such as domain organization, oligomerization degree or regulatory mechanisms, are not conserved across the eukaryotes. The current body of knowledge is insufficient to understand these differences and their impact on CBS function and physiology. To overcome this deficiency, we have addressed the crystallization and preliminary crystallographic analysis of a protein construct (hCBS516-525) that contains the full-length CBS from Homo sapiens (hCBS) and just lacks amino-acid residues 516-525, which are located in a disordered loop. The human enzyme yielded crystals belonging to space group I222, with unit-cell parameters a=124.98, b=136.33, c=169.83 Å and diffracting X-rays to a resolution of 3.0 Å. The crystal structure appears to contain two molecules in the asymmetric unit which presumably correspond to a dimeric form of the enzyme.
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Affiliation(s)
- Iker Oyenarte
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain
| | - Tomas Majtan
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - June Ereño
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain
| | | | - Jan P. Kraus
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Luis Alfonso Martínez-Cruz
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain
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1430
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Lehtimäki M, Laulumaa S, Ruskamo S, Kursula P. Production and crystallization of a panel of structure-based mutants of the human myelin peripheral membrane protein P2. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1359-62. [PMID: 23143249 PMCID: PMC3515381 DOI: 10.1107/s1744309112039036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 09/12/2012] [Indexed: 11/10/2022]
Abstract
The myelin sheath is a multilayered membrane that surrounds and insulates axons in the nervous system. One of the proteins specific to the peripheral nerve myelin is P2, a protein that is able to stack lipid bilayers. With the goal of obtaining detailed information on the structure-function relationship of P2, 14 structure-based mutated variants of human P2 were generated and produced. The mutants were designed to potentially affect the binding of lipid bilayers by P2. All mutated variants were also crystallized and preliminary crystallographic data are presented. The structural data from the mutants will be combined with diverse functional assays in order to elucidate the fine details of P2 function at the molecular level.
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Affiliation(s)
- Mari Lehtimäki
- Department of Biochemistry and Biocenter Oulu, Universtity of Oulu, PO Box 3000, 90014 Oulu, Finland
| | - Saara Laulumaa
- Department of Biochemistry and Biocenter Oulu, Universtity of Oulu, PO Box 3000, 90014 Oulu, Finland
- CSSB–HZI, DESY, Notkestrasse 85, 22603 Hamburg, Germany
| | - Salla Ruskamo
- Department of Biochemistry and Biocenter Oulu, Universtity of Oulu, PO Box 3000, 90014 Oulu, Finland
| | - Petri Kursula
- Department of Biochemistry and Biocenter Oulu, Universtity of Oulu, PO Box 3000, 90014 Oulu, Finland
- CSSB–HZI, DESY, Notkestrasse 85, 22603 Hamburg, Germany
- Department of Chemistry, University of Hamburg, Hamburg, Germany
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1431
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Oyenarte I, Majtan T, Ereño J, Corral-Rodríguez MA, Klaudiny J, Majtan J, Kraus JP, Martínez-Cruz LA. Purification, crystallization and preliminary crystallographic analysis of the full-length cystathionine β-synthase from Apis mellifera. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1323-8. [PMID: 23143241 PMCID: PMC3515373 DOI: 10.1107/s1744309112038638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 09/08/2012] [Indexed: 11/10/2022]
Abstract
Cystathionine β-synthase (CBS) is a pyridoxal-5'-phosphate-dependent enzyme that catalyzes the first step of the transsulfuration pathway, namely the condensation of serine with homocysteine to form cystathionine. Mutations in the CBS gene are the single most common cause of hereditary homocystinuria, a multisystemic disease affecting to various extents the vasculature, connective tissues and central nervous system. At present, the crystal structure of CBS from Drosophila melanogaster is the only available structure of the full-length enzyme. Here we describe a cloning, overexpression, purification and preliminary crystallographic analysis of a full-length CBS from Apis mellifera (AmCBS) which maintains 51 and 46% sequence identity with its Drosophila and human homologs, respectively. The AmCBS yielded crystals belonging to space group P2(1)2(1)2(1), with unit-cell parameters a=85.90, b=95.87, c=180.33 Å. Diffraction data were collected to a resolution of 3.0 Å. The crystal structure contained two molecules in the asymmetric unit which presumably correspond to the dimeric species observed in solution.
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Affiliation(s)
- Iker Oyenarte
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain
| | - Tomas Majtan
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - June Ereño
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain
| | | | - Jaroslav Klaudiny
- Institute of Zoology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, 845 06, Slovakia
| | - Juraj Majtan
- Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, 845 38, Slovakia
| | - Jan P. Kraus
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Luis Alfonso Martínez-Cruz
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia, Edificio 800, Derio, Bizkaia 48160, Spain
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1432
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Neumann P, Brodhun F, Sauer K, Herrfurth C, Hamberg M, Brinkmann J, Scholz J, Dickmanns A, Feussner I, Ficner R. Crystal structures of Physcomitrella patens AOC1 and AOC2: insights into the enzyme mechanism and differences in substrate specificity. PLANT PHYSIOLOGY 2012; 160:1251-66. [PMID: 22987885 PMCID: PMC3490582 DOI: 10.1104/pp.112.205138] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 09/14/2012] [Indexed: 05/18/2023]
Abstract
In plants, oxylipins regulate developmental processes and defense responses. The first specific step in the biosynthesis of the cyclopentanone class of oxylipins is catalyzed by allene oxide cyclase (AOC) that forms cis(+)-12-oxo-phytodienoic acid. The moss Physcomitrella patens has two AOCs (PpAOC1 and PpAOC2) with different substrate specificities for C₁₈- and C₂₀-derived substrates, respectively. To better understand AOC's catalytic mechanism and to elucidate the structural properties that explain the differences in substrate specificity, we solved and analyzed the crystal structures of 36 monomers of both apo and ligand complexes of PpAOC1 and PpAOC2. From these data, we propose the following intermediates in AOC catalysis: (1) a resting state of the apo enzyme with a closed conformation, (2) a first shallow binding mode, followed by (3) a tight binding of the substrate accompanied by conformational changes in the binding pocket, and (4) initiation of the catalytic cycle by opening of the epoxide ring. As expected, the substrate dihydro analog cis-12,13S-epoxy-9Z,15Z-octadecadienoic acid did not cyclize in the presence of PpAOC1; however, when bound to the enzyme, it underwent isomerization into the corresponding trans-epoxide. By comparing complex structures of the C₁₈ substrate analog with in silico modeling of the C₂₀ substrate analog bound to the enzyme allowed us to identify three major molecular determinants responsible for the different substrate specificities (i.e. larger active site diameter, an elongated cavity of PpAOC2, and two nonidentical residues at the entrance of the active site).
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1433
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Abstract
Gene transcription by RNA polymerase (Pol) II requires the coactivator complex Mediator. Mediator connects transcriptional regulators and Pol II, and is linked to human disease. Mediator from the yeast Saccharomyces cerevisiae has a molecular mass of 1.4 megadaltons and comprises 25 subunits that form the head, middle, tail and kinase modules. The head module constitutes one-half of the essential Mediator core, and comprises the conserved subunits Med6, Med8, Med11, Med17, Med18, Med20 and Med22. Recent X-ray analysis of the S. cerevisiae head module at 4.3 Å resolution led to a partial architectural model with three submodules called neck, fixed jaw and moveable jaw. Here we determine de novo the crystal structure of the head module from the fission yeast Schizosaccharomyces pombe at 3.4 Å resolution. Structure solution was enabled by new structures of Med6 and the fixed jaw, and previous structures of the moveable jaw and part of the neck, and required deletion of Med20. The S. pombe head module resembles the head of a crocodile with eight distinct elements, of which at least four are mobile. The fixed jaw comprises tooth and nose domains, whereas the neck submodule contains a helical spine and one limb, with shoulder, arm and finger elements. The arm and the essential shoulder contact other parts of Mediator. The jaws and a central joint are implicated in interactions with Pol II and its carboxy-terminal domain, and the joint is required for transcription in vitro. The S. pombe head module structure leads to a revised model of the S. cerevisiae module, reveals a high conservation and flexibility, explains known mutations, and provides the basis for unravelling a central mechanism of gene regulation.
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1434
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Crystal structure of the Leishmania major peroxidase-cytochrome c complex. Proc Natl Acad Sci U S A 2012; 109:18390-4. [PMID: 23100535 DOI: 10.1073/pnas.1213295109] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The causative agent of leishmaniasis is the protozoan parasite Leishmania major. Part of the host protective mechanism is the production of reactive oxygen species including hydrogen peroxide. In response, L. major produces a peroxidase, L. major peroxidase (LmP), that helps to protect the parasite from oxidative stress. LmP is a heme peroxidase that catalyzes the peroxidation of mitochondrial cytochrome c. We have determined the crystal structure of LmP in a complex with its substrate, L. major cytochrome c (LmCytc) to 1.84 Å, and compared the structure to its close homolog, the yeast cytochrome c peroxidase-cytochrome c complex. The binding interface between LmP and LmCytc has one strong and one weak ionic interaction that the yeast system lacks. The differences between the steady-state kinetics correlate well with the Lm redox pair being more dependent on ionic interactions, whereas the yeast redox pair depends more on nonpolar interactions. Mutagenesis studies confirm that the ion pairs at the intermolecular interface are important to both k(cat) and K(M). Despite these differences, the electron transfer path, with respect to the distance between hemes, along the polypeptide chain is exactly the same in both redox systems. A potentially important difference, however, is the side chains involved. LmP has more polar groups (Asp and His) along the pathway compared with the nonpolar groups (Leu and Ala) in the yeast system, and as a result, the electrostatic environment along the presumed electron transfer path is substantially different.
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1435
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Koh CY, Kim JE, Shibata S, Ranade RM, Yu M, Liu J, Gillespie JR, Buckner FS, Verlinde CL, Fan E, Hol WG. Distinct states of methionyl-tRNA synthetase indicate inhibitor binding by conformational selection. Structure 2012; 20:1681-91. [PMID: 22902861 PMCID: PMC3472110 DOI: 10.1016/j.str.2012.07.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Revised: 07/18/2012] [Accepted: 07/20/2012] [Indexed: 02/07/2023]
Abstract
To guide development of new drugs targeting methionyl-tRNA synthetase (MetRS) for treatment of human African trypanosomiasis, crystal structure determinations of Trypanosoma brucei MetRS in complex with its substrate methionine and its intermediate product methionyl-adenylate were followed by those of the enzyme in complex with high-affinity aminoquinolone inhibitors via soaking experiments. Drastic changes in conformation of one of the two enzymes in the asymmetric unit allowed these inhibitors to occupy an enlarged methionine pocket and a new so-called auxiliary pocket. Interestingly, a small low-affinity compound caused the same conformational changes, removed the methionine without occupying the methionine pocket, and occupied the previously not existing auxiliary pocket. Analysis of these structures indicates that the binding of the inhibitors is the result of conformational selection, not induced fit.
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Affiliation(s)
- Cho Yeow Koh
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Jessica E. Kim
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Ranae M. Ranade
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Mingyan Yu
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Shandong University, No. 44 Wenhuaxi Road, Jinan 250012, P.R. China
| | - Jiyun Liu
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - J. Robert Gillespie
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Frederick S. Buckner
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Wim G.J. Hol
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA,Correspondence to:
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1436
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Coelho C, Mahro M, Trincão J, Carvalho ATP, Ramos MJ, Terao M, Garattini E, Leimkühler S, Romão MJ. The first mammalian aldehyde oxidase crystal structure: insights into substrate specificity. J Biol Chem 2012; 287:40690-702. [PMID: 23019336 DOI: 10.1074/jbc.m112.390419] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Aldehyde oxidases have pharmacological relevance, and AOX3 is the major drug-metabolizing enzyme in rodents. RESULTS The crystal structure of mouse AOX3 with kinetics and molecular docking studies provides insights into its enzymatic characteristics. CONCLUSION Differences in substrate and inhibitor specificities can be rationalized by comparing the AOX3 and xanthine oxidase structures. SIGNIFICANCE The first aldehyde oxidase structure represents a major advance for drug design and mechanistic studies. Aldehyde oxidases (AOXs) are homodimeric proteins belonging to the xanthine oxidase family of molybdenum-containing enzymes. Each 150-kDa monomer contains a FAD redox cofactor, two spectroscopically distinct [2Fe-2S] clusters, and a molybdenum cofactor located within the protein active site. AOXs are characterized by broad range substrate specificity, oxidizing different aldehydes and aromatic N-heterocycles. Despite increasing recognition of its role in the metabolism of drugs and xenobiotics, the physiological function of the protein is still largely unknown. We have crystallized and solved the crystal structure of mouse liver aldehyde oxidase 3 to 2.9 Å. This is the first mammalian AOX whose structure has been solved. The structure provides important insights into the protein active center and further evidence on the catalytic differences characterizing AOX and xanthine oxidoreductase. The mouse liver aldehyde oxidase 3 three-dimensional structure combined with kinetic, mutagenesis data, molecular docking, and molecular dynamics studies make a decisive contribution to understand the molecular basis of its rather broad substrate specificity.
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Affiliation(s)
- Catarina Coelho
- Requimte, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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Perkins A, Gretes MC, Nelson KJ, Poole LB, Karplus PA. Mapping the active site helix-to-strand conversion of CxxxxC peroxiredoxin Q enzymes. Biochemistry 2012; 51:7638-50. [PMID: 22928725 DOI: 10.1021/bi301017s] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Peroxiredoxins (Prx) make up a family of enzymes that reduce peroxides using a peroxidatic cysteine residue; among these, members of the PrxQ subfamily are proposed to be the most ancestral-like yet are among the least characterized. In many PrxQ enzymes, a second "resolving" cysteine is located five residues downstream from the peroxidatic Cys, and these residues form a disulfide during the catalytic cycle. Here, we describe three hyperthermophilic PrxQ crystal structures originally determined by the RIKEN structural genomics group. We reprocessed the diffraction data and conducted further refinement to yield models with R(free) values lowered by 2.3-7.2% and resolution extended by 0.2-0.3 Å, making one, at 1.4 Å, one of the best resolved peroxiredoxins to date. Comparisons of two matched thiol and disulfide forms reveal that the active site conformational change required for disulfide formation involves a transition of ~20 residues from a pair of α-helices to a β-hairpin and 3(10)-helix. Each conformation has ~10 residues with a high level of disorder providing slack that allows the dramatic shift, and the two conformations are anchored to the protein core by distinct nonpolar side chains that fill three hydrophobic pockets. Sequence conservation patterns confirm the importance of these and a few additional residues for function. From a broader perspective, this study raises the provocative question of how to make use of the valuable information in the Protein Data Bank generated by structural genomics projects but not described in the literature, perhaps remaining unrecognized and certainly underutilized.
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Affiliation(s)
- Arden Perkins
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
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Affiliation(s)
- Phil Evans
- MRC Laboratory of Molecular Biology, Cambridge, UK.
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