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Nan J, Eguiraun M, Bolmsten F, Ote AM, Nardella A, Ursby T, Unge J, Thunnissen MMGM, Mueller U. Novel data collection and processing strategies for the next generation X-ray source MAX IV. Acta Crystallogr A Found Adv 2016. [DOI: 10.1107/s2053273316097187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Awad W, Svensson Birkedal G, Thunnissen MMGM, Mani K, Logan DT. Improvements in the order, isotropy and electron density of glypican-1 crystals by controlled dehydration. Acta Crystallogr D Biol Crystallogr 2013; 69:2524-33. [PMID: 24311593 PMCID: PMC3852657 DOI: 10.1107/s0907444913025250] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/11/2013] [Indexed: 01/15/2023]
Abstract
The use of controlled dehydration for improvement of protein crystal diffraction quality is increasing in popularity, although there are still relatively few documented examples of success. A study has been carried out to establish whether controlled dehydration could be used to improve the anisotropy of crystals of the core protein of the human proteoglycan glypican-1. Crystals were subjected to controlled dehydration using the HC1 device. The optimal protocol for dehydration was developed by careful investigation of the following parameters: dehydration rate, final relative humidity and total incubation time Tinc. Of these, the most important was shown to be Tinc. After dehydration using the optimal protocol the crystals showed significantly reduced anisotropy and improved electron density, allowing the building of previously disordered parts of the structure.
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Affiliation(s)
- Wael Awad
- Department of Biochemistry and Structural Biology, Centre for Molecular Protein Science, Lund University, Box 124, 221 00 Lund, Sweden
- Department of Biophysics, Faculty of Science, Cairo University, Cairo, Egypt
| | - Gabriel Svensson Birkedal
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, 221 84 Lund, Sweden
| | - Marjolein M. G. M. Thunnissen
- Department of Biochemistry and Structural Biology, Centre for Molecular Protein Science, Lund University, Box 124, 221 00 Lund, Sweden
- MAX IV Laboratory, Lund University, Box 188, 221 00 Lund, Sweden
| | - Katrin Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, Biomedical Center A13, 221 84 Lund, Sweden
| | - Derek T. Logan
- Department of Biochemistry and Structural Biology, Centre for Molecular Protein Science, Lund University, Box 124, 221 00 Lund, Sweden
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3
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Thunnissen MMGM, Logan DT, Ursby T. BioMAX: the first MX beamline at MAX IV. Acta Crystallogr A 2013. [DOI: 10.1107/s0108767313096517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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Ursby T, Unge J, Appio R, Logan DT, Fredslund F, Svensson C, Larsson K, Labrador A, Thunnissen MMGM. The macromolecular crystallography beamline I911-3 at the MAX IV laboratory. J Synchrotron Radiat 2013; 20:648-53. [PMID: 23765310 PMCID: PMC3943556 DOI: 10.1107/s0909049513011734] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/29/2013] [Indexed: 05/12/2023]
Abstract
The macromolecular crystallography beamline I911-3, part of the Cassiopeia/I911 suite of beamlines, is based on a superconducting wiggler at the MAX II ring of the MAX IV Laboratory in Lund, Sweden. The beamline is energy-tunable within a range between 6 and 18 keV. I911-3 opened for users in 2005. In 2010-2011 the experimental station was completely rebuilt and refurbished such that it has become a state-of-the-art experimental station with better possibilities for rapid throughput, crystal screening and work with smaller samples. This paper describes the complete I911-3 beamline and how it is embedded in the Cassiopeia suite of beamlines.
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Affiliation(s)
- Thomas Ursby
- MAX IV Laboratory, Lund University, POB 118, Lund SE-221 00, Sweden.
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5
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Helgstrand C, Hasan M, Uysal H, Haeggström JZ, Thunnissen MMGM. A leukotriene A4 hydrolase-related aminopeptidase from yeast undergoes induced fit upon inhibitor binding. J Mol Biol 2010; 406:120-34. [PMID: 21146536 DOI: 10.1016/j.jmb.2010.11.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 11/24/2010] [Accepted: 11/30/2010] [Indexed: 01/24/2023]
Abstract
Vertebrate leukotriene A(4) hydrolases are bifunctional zinc metalloenzymes with an epoxide hydrolase and an aminopeptidase activity. In contrast, highly homologous enzymes from lower organisms only have the aminopeptidase activity. From sequence comparisons, it is not clear why this difference occurs. In order to obtain more information on the evolutionary relationship between these enzymes and their activities, the structure of a closely related leucine aminopeptidase from Saccharomyces cerevisiae that only shows a very low epoxide hydrolase activity was determined. To investigate the molecular architecture of the active site, the structures of both the native protein and the protein in complex with the aminopeptidase inhibitor bestatin were solved. These structures show a more spacious active site, and the protected cavity in which the labile substrate leukotriene A(4) is bound in the human enzyme is partially obstructed and in other parts is more solvent accessible. Furthermore, the enzyme undergoes induced fit upon binding of the inhibitor bestatin, leading to a movement of the C-terminal domain. The main triggers for the domain movement are a conformational change of Tyr312 and a subtle change in backbone conformation of the PYGAMEN fingerprint region for peptide substrate recognition. This leads to a change in the hydrogen-bonding network pulling the C-terminal domain into a different position. Inasmuch as bestatin is a structural analogue of a leucyl dipeptide and may be regarded as a transition state mimic, our results imply that the enzyme undergoes induced fit during substrate binding and turnover.
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Affiliation(s)
- Charlotte Helgstrand
- Centre of Molecular Protein Science, Lund University, Getingevägen 60, SE 22100 Lund, Sweden
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6
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Nurmemmedov E, Yengo RK, Ladomery MR, Thunnissen MMGM. Kinetic behaviour of WT 1's zinc finger domain in binding to the alpha-actinin-1 mRNA. Arch Biochem Biophys 2010; 497:21-7. [PMID: 20193655 DOI: 10.1016/j.abb.2010.02.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 02/23/2010] [Accepted: 02/24/2010] [Indexed: 12/13/2022]
Abstract
The zinc finger transcription factor Wilms tumour protein (WT 1) is known for its essential involvement in the development of the genitourinary system as well as of other organs and tissues. WT 1 is capable of selectively binding either DNA or mRNA targets. A KTS insertion due to alternative splicing between the zinc fingers 3 and 4 and an unconventional zinc finger 1 are the unique features that distinguish WT 1 from classical DNA-binding C(2)H(2)-type zinc finger proteins. The DNA binding characteristics of WT 1 are well studied. Due to lack of information about its native RNA targets, no extensive research has been directed at how WT 1 binds RNA. Using surface plasmon resonance, this study attempts to understand the binding behaviour of WT 1 zinc fingers with its recently reported and first putative mRNA target, ACT 34, whose stem-loop structure is believed to be critical for the interactions with WT 1. We have analysed the interactions of five WT 1 zinc finger truncations with wild-type ACT 34 and four variants. Our results indicate that WT 1 zinc fingers bind ACT 34 in a specific manner, and that this occurs as interplay of all four zinc fingers. We also report that a sensitive kinetic balance, which is equilibrated by both zinc finger 1 and KTS, regulates the interaction with ACT 34. The stem-loop and the flanking nucleotides are important elements for specific recognition by WT 1 zinc fingers.
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Affiliation(s)
- Elmar Nurmemmedov
- Molecular Biophysics, Chemical Center, Lund University, 221 00 Lund, Sweden.
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Nurmemmedov E, Yengo RK, Uysal H, Karlsson R, Thunnissen MMGM. New insights into DNA-binding behavior of Wilms tumor protein (WT1)--a dual study. Biophys Chem 2009; 145:116-25. [PMID: 19853363 DOI: 10.1016/j.bpc.2009.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 09/20/2009] [Accepted: 09/22/2009] [Indexed: 02/03/2023]
Abstract
Wilms Tumor suppressor protein (WT1) is a transcription factor that is involved in a variety of developmental functions during organ development. It is also implicated in the pathology of several different cancer forms. The protein contains four C(2)H(2)-type zinc fingers and it specifically binds GC-rich sequences in the promoter regions of its target genes, which are either up or down regulated. Two properties make WT1 a more unusual transcription factor - an unconventional amino acid composition for zinc finger 1, and the insertion of a tri-peptide KTS in some of the splice isoforms of WT1. Using six WT1 constructs in which zinc fingers are systematically deleted, a dual study based on a bacterial 1-hybrid system and surface plasmon resonance measurements is performed. The experiments show that the effect of zinc finger 1 is not significant in terms of overall DNA-binding kinetics, however it influences both the specificity of target recognition and stability of interaction in presence of KTS. The KTS insertion, however, only mildly retards binding affinity, mainly by affecting the on-rate. We suggest that the insertion disturbs zinc finger 4 from its binding frame, thus weakening the rate of target recognition. Finally, for the construct in which both zinc fingers 1 and 4 were deleted, the two middle fingers 2-3 still could function as a 'minimal DNA-recognition domain' for WT1, however the formation of a stable protein-DNA complex is impaired since the overall affinity was dramatically reduced mainly since the off-rate was severely affected.
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Affiliation(s)
- Elmar Nurmemmedov
- Center for Molecular Protein Science, Lund University, Getingevägen 60, 221 00, Lund, Sweden
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Uysal H, Bockermann R, Nandakumar KS, Sehnert B, Bajtner E, Engström A, Serre G, Burkhardt H, Thunnissen MMGM, Holmdahl R. Structure and pathogenicity of antibodies specific for citrullinated collagen type II in experimental arthritis. ACTA ACUST UNITED AC 2009; 206:449-62. [PMID: 19204106 PMCID: PMC2646582 DOI: 10.1084/jem.20081862] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Antibodies to citrulline-modified proteins have a high diagnostic value in rheumatoid arthritis (RA). However, their biological role in disease development is still unclear. To obtain insight into this question, a panel of mouse monoclonal antibodies was generated against a major triple helical collagen type II (CII) epitope (position 359-369; ARGLTGRPGDA) with or without arginines modified by citrullination. These antibodies bind cartilage and synovial tissue, and mediate arthritis in mice. Detection of citrullinated CII from RA patients' synovial fluid demonstrates that cartilage-derived CII is indeed citrullinated in vivo. The structure determination of a Fab fragment of one of these antibodies in complex with a citrullinated peptide showed a surprising beta-turn conformation of the peptide and provided information on citrulline recognition. Based on these findings, we propose that autoimmunity to CII, leading to the production of antibodies specific for both native and citrullinated CII, is an important pathogenic factor in the development of RA.
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Affiliation(s)
- Hüseyin Uysal
- Center for Molecular Protein Science, Biomedical Center I11, Lund University, 221 00 Lund, Sweden
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9
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Tholander F, Muroya A, Roques BP, Fournié-Zaluski MC, Thunnissen MMGM, Haeggström JZ. Structure-based dissection of the active site chemistry of leukotriene A4 hydrolase: implications for M1 aminopeptidases and inhibitor design. ACTA ACUST UNITED AC 2008; 15:920-9. [PMID: 18804029 DOI: 10.1016/j.chembiol.2008.07.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 07/26/2008] [Accepted: 07/31/2008] [Indexed: 11/29/2022]
Abstract
M1 aminopeptidases comprise a large family of biologically important zinc enzymes. We show that peptide turnover by the M1 prototype, leukotriene A4 hydrolase/aminopeptidase, involves a shift in substrate position associated with exchange of zinc coordinating groups, while maintaining the overall coordination geometry. The transition state is stabilized by residues conserved among M1 members and in the final reaction step, Glu-296 of the canonical zinc binding HEXXH motif shuffles a proton from the hydrolytic water to the leaving group. Tripeptide substrates bind along the conserved GXMEN motif, precisely occupying the distance between Glu-271 and Arg-563, whereas the Arg specificity is governed by a narrow S1 pocket capped with Asp-375. Our data provide detailed insights to the active site chemistry of M1 aminopeptidases and will aid in the development of novel enzyme inhibitors.
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Affiliation(s)
- Fredrik Tholander
- Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institute, Stockholm, Sweden
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Uysal H, Sehnert B, Nandakumar KS, Böiers U, Burkhardt H, Holmdahl R, Thunnissen MMGM. The crystal structure of the pathogenic collagen type II-specific mouse monoclonal antibody CIIC1 Fab: structure to function analysis. Mol Immunol 2008; 45:2196-204. [PMID: 18241923 DOI: 10.1016/j.molimm.2007.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 11/08/2007] [Accepted: 12/05/2007] [Indexed: 11/28/2022]
Abstract
Monoclonal anti-collagen type II antibody CIIC1 is an arthritogenic autoantibody, which induces arthritis in mice. We crystallized and solved the structure of CIIC1 Fab molecule. Analysis of structure revealed an interaction between the CDR regions of one Fab to the CH1 domain of another Fab, which resembles an antibody-antigen interaction. ELISA experiments confirmed the cross-reactivity of both the full CIIC1 antibody and a single chain Fv fragment to other anti-collagen antibodies which are of different isotypes and epitope specificity. The rheumatoid factor like reactivity of CIIC1 antibody together with its collagen type II specificity may explain the pathogenicity of this antibody.
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Affiliation(s)
- Hüseyin Uysal
- Department of Molecular Biophysics, Lund University, Chemical Center, Box 124, SE 221 00, Lund, Sweden
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11
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Tholander F, Kull F, Ohlson E, Shafqat J, Thunnissen MMGM, Haeggström JZ. Leukotriene A4 Hydrolase, Insights into the Molecular Evolution by Homology Modeling and Mutational Analysis of Enzyme from Saccharomyces cerevisiae. J Biol Chem 2005; 280:33477-86. [PMID: 16024909 DOI: 10.1074/jbc.m506821200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian leukotriene A4 (LTA4) hydrolase is a bifunctional zinc metalloenzyme possessing an Arg/Ala aminopeptidase and an epoxide hydrolase activity, which converts LTA4 into the chemoattractant LTB4. We have previously cloned an LTA4 hydrolase from Saccharomyces cerevisiae with a primitive epoxide hydrolase activity and a Leu aminopeptidase activity, which is stimulated by LTA4. Here we used a modeled structure of S. cerevisiae LTA4 hydrolase, mutational analysis, and binding studies to show that Glu-316 and Arg-627 are critical for catalysis, allowing us to a propose a mechanism for the epoxide hydrolase activity. Guided by the structure, we engineered S. cerevisiae LTA4 hydrolase to attain catalytic properties resembling those of human LTA4 hydrolase. Thus, six consecutive point mutations gradually introduced a novel Arg aminopeptidase activity and caused the specific Ala and Pro aminopeptidase activities to increase 24 and 63 times, respectively. In contrast to the wild type enzyme, the hexuple mutant was inhibited by LTA4 for all tested substrates and to the same extent as for the human enzyme. In addition, these mutations improved binding of LTA4 and increased the relative formation of LTB4, whereas the turnover of this substrate was only weakly affected. Our results suggest that during evolution, the active site of an ancestral eukaryotic zinc aminopeptidase has been reshaped to accommodate lipid substrates while using already existing catalytic residues for a novel, gradually evolving, epoxide hydrolase activity. Moreover, the unique ability to catalyze LTB4 synthesis appears to be the result of multiple and subtle structural rearrangements at the catalytic center rather than a limited set of specific amino acid substitutions.
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Affiliation(s)
- Fredrik Tholander
- Department of Medical Biochemistry and Biophysics, Divisions of Chemistry 1 and 2, Karolinska Institutet, Stockholm S-171 77, Sweden
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12
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Abstract
Leukotriene (LT) A(4) hydrolase is a bifunctional zinc metalloenzyme, which converts LTA(4) into the neutrophil chemoattractant LTB(4) and also exhibits an anion-dependent aminopeptidase activity. In the x-ray crystal structure of LTA(4) hydrolase, Arg(563) and Lys(565) are found at the entrance of the active center. Here we report that replacement of Arg(563), but not Lys(565), leads to complete abrogation of the epoxide hydrolase activity. However, mutations of Arg(563) do not seem to affect substrate binding strength, because values of K(i) for LTA(4) are almost identical for wild type and (R563K)LTA(4) hydrolase. These results are supported by the 2.3-A crystal structure of (R563A)LTA(4) hydrolase, which does not reveal structural changes that can explain the complete loss of enzyme function. For the aminopeptidase reaction, mutations of Arg(563) reduce the catalytic activity (V(max) = 0.3-20%), whereas mutations of Lys(565) have limited effect on catalysis (V(max) = 58-108%). However, in (K565A)- and (K565M)LTA(4) hydrolase, i.e. mutants lacking a positive charge, values of the Michaelis constant for alanine-p-nitroanilide increase significantly (K(m) = 480-640%). Together, our data indicate that Arg(563) plays an unexpected, critical role in the epoxide hydrolase reaction, presumably in the positioning of the carboxylate tail to ensure perfect substrate alignment along the catalytic elements of the active site. In the aminopeptidase reaction, Arg(563) and Lys(565) seem to cooperate to provide sufficient binding strength and productive alignment of the substrate. In conclusion, Arg(563) and Lys(565) possess distinct roles as carboxylate recognition sites for two chemically different substrates, each of which is turned over in separate enzymatic reactions catalyzed by LTA(4) hydrolase.
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Affiliation(s)
- Peter C Rudberg
- Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institutet, S-171 77 Stockholm, Sweden
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Andersson B, Kull F, Haeggström JZ, Thunnissen MMGM. Crystallization and X-ray diffraction data analysis of leukotriene A4 hydrolase from Saccharomyces cerevisiae. Acta Crystallogr D Biol Crystallogr 2003; 59:1093-5. [PMID: 12777785 DOI: 10.1107/s0907444903007728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2003] [Accepted: 04/07/2003] [Indexed: 11/10/2022]
Abstract
The Saccharomyces cerevisiae leukotriene A4 (LTA4) hydrolase (scLTA4 hydrolase) has been crystallized in order to study the two activities of LTA4 hydrolase in an evolutionary perspective. Single well diffracting crystals are obtained after switching from the hanging-drop method to liquid-liquid diffusion in capillaries using PEG 8000 as precipitant. These crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 70.8, b = 98.1, c = 99.2 A. Intensity data to 2.3 A resolution were collected from a native scLTA4 hydrolase crystal using synchrotron radiation. A molecular-replacement solution was obtained using the human LTA4 hydrolase structure and the program BEAST.
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Affiliation(s)
- Björn Andersson
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
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14
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Thunnissen MMGM, Andersson B, Samuelsson B, Wong CH, Haeggström JZ. Crystal structures of leukotriene A4 hydrolase in complex with captopril and two competitive tight-binding inhibitors. FASEB J 2002; 16:1648-50. [PMID: 12207002 DOI: 10.1096/fj.01-1017fje] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Leukotriene (LT) A4 hydrolase/aminopeptidase is a bifunctional zinc enzyme that catalyzes the final step in the biosynthesis of LTB4, a potent chemoattractant and immune modulating lipid mediator. Here, we report a high-resolution crystal structure of LTA4 hydrolase in complex with captopril, a classical inhibitor of the zinc peptidase angiotensin-converting enzyme. Captopril makes few interactions with the protein, but its free thiol group is bound to the zinc, apparently accounting for most of its inhibitory action on LTA4 hydrolase. In addition, we have determined the structures of LTA4 hydrolase in complex with two selective tight-binding inhibitors, a thioamine and a hydroxamic acid. Their common benzyloxyphenyl tail, designed to mimic the carbon backbone of LTA4, binds into a narrow hydrophobic cavity in the protein. The free hydroxyl group of the hydroxamic acid makes a suboptimal, monodentate complex with the zinc, and strategies for improved inhibitor design can be deduced from the structure. Taken together, the three crystal structures provide the molecular basis for the divergent pharmacological profiles of LTA4 hydrolase inhibitors. Moreover, they help define the binding pocket for the fatty acid-derived epoxide LTA4 as well as the subsites for a tripeptide substrate, which in turn have important implications for the molecular mechanisms of enzyme catalyses.
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Affiliation(s)
- Marjolein M G M Thunnissen
- Department of Biochemistry, University of Stockholm, Arrhenius Laboratories A4, S-106 91 Stockholm, Sweden
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15
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Abstract
The leukotrienes (LTs) are a family of lipid mediators involved in inflammation and allergy. Leukotriene B4 is a classical chemoattractant, which triggers adherence and aggregation of leukocytes to the endothelium at only nanomolar concentrations. In addition, leukotriene B4 modulates immune responses, participates in the host-defense against infections, and is a key mediator of PAF-induced lethal shock. Because of these powerful biological effects, leukotriene B4 is implicated in a variety of acute and chronic inflammatory diseases, e.g. nephritis, arthritis, dermatitis, and chronic obstructive pulmonary disease. The final step in the biosynthesis of leukotriene B4 is catalyzed by leukotriene A4 hydrolase, a unique bi-functional zinc metalloenzyme with an anion-dependent aminopeptidase activity. Here we describe the most recent developments regarding our understanding of the structure, function, and catalytic mechanisms of leukotriene A4 hydrolase.
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Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
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16
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Haeggström JZ, Nordlund P, Thunnissen MMGM. Functional properties and molecular architecture of leukotriene A4 hydrolase, a pivotal catalyst of chemotactic leukotriene formation. ScientificWorldJournal 2002; 2:1734-49. [PMID: 12806167 PMCID: PMC6009643 DOI: 10.1100/tsw.2002.810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The leukotrienes are a family of lipid mediators involved in inflammation and allergy. Leukotriene B4 is a classical chemoattractant, which triggers adherence and aggregation of leukocytes to the endothelium at only nM concentrations. In addition, leukotriene B4 modulates immune responses, participates in the host defense against infections, and is a key mediator of PAF-induced lethal shock. Because of these powerful biological effects, leukotriene B4 is implicated in a variety of acute and chronic inflammatory diseases, e.g., nephritis, arthritis, dermatitis, and chronic obstructive pulmonary disease. The final step in the biosynthesis of leukotriene B4 is catalyzed by leukotriene A4 hydrolase, a unique bifunctional zinc metalloenzyme with an anion-dependent aminopeptidase activity. Here we describe the most recent developments regarding our understanding of the function and molecular architecture of leukotriene A4 hydrolase.
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Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Division of Chemistry 2, Karolinska Institutet, S-171 77 Stockholm, Sweden.
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17
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Rudberg PC, Tholander F, Thunnissen MMGM, Samuelsson B, Haeggstrom JZ. Leukotriene A4 hydrolase: selective abrogation of leukotriene B4 formation by mutation of aspartic acid 375. Proc Natl Acad Sci U S A 2002; 99:4215-20. [PMID: 11917124 PMCID: PMC123628 DOI: 10.1073/pnas.072090099] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2002] [Indexed: 11/18/2022] Open
Abstract
Leukotriene A4 (LTA4, 5S-trans-5,6-oxido-7,9-trans-11,14-cis-eicosatetraenoic acid) hydrolase (LTA4H)/aminopeptidase is a bifunctional zinc metalloenzyme that catalyzes the final and rate-limiting step in the biosynthesis of leukotriene B4 (LTB4, 5S,12R-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid), a classical chemoattractant and immune modulating lipid mediator. Two chemical features are key to the bioactivity of LTB4, namely, the chirality of the 12R-hydroxyl group and the cis-trans-trans geometry of the conjugated triene structure. From the crystal structure of LTA4H, a hydrophilic patch composed of Gln-134, Tyr-267, and Asp-375 was identified in a narrow and otherwise hydrophobic pocket, believed to bind LTA4. In addition, Asp-375 belongs to peptide K21, a previously characterized 21-residue active site-peptide to which LTA4 binds during suicide inactivation. In the present report we used site-directed mutagenesis and x-ray crystallography to show that Asp-375, but none of the other candidate residues, is specifically required for the epoxide hydrolase activity of LTA4H. Thus, mutation of Asp-375 leads to a selective loss of the enzyme's ability to generate LTB4 whereas the aminopeptidase activity is preserved. We propose that Asp-375, possibly assisted by Gln-134, acts as a critical determinant for the stereoselective introduction of the 12R-hydroxyl group and thus the biological activity of LTB4.
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Affiliation(s)
- Peter C Rudberg
- Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institutet, S-171 77 Stockholm, Sweden
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Rudberg PC, Tholander F, Thunnissen MMGM, Haeggström JZ. Leukotriene A4 hydrolase/aminopeptidase. Glutamate 271 is a catalytic residue with specific roles in two distinct enzyme mechanisms. J Biol Chem 2002; 277:1398-404. [PMID: 11675384 DOI: 10.1074/jbc.m106577200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leukotriene A(4) hydrolase/aminopeptidase is a bifunctional zinc metalloenzyme that converts the fatty acid epoxide leukotriene A(4) into leukotriene B(4), a potent chemoattractant and immune-modulating lipid mediator. Recently, the structure of leukotriene A(4) hydrolase revealed that Glu-271, which belongs to a conserved GXMEN motif in the M1 family of zinc peptidases, and Gln-136 are located at the active site. Here we report that mutagenetic replacements of Glu-271, but not Gln-136, abrogate both catalytic activities of leukotriene A(4) hydrolase. Furthermore, the 2.1 A crystal structure of [E271Q]leukotriene A(4) hydrolase revealed minimal conformational changes that could not explain the loss of enzyme function. We propose that the carboxylate of Glu-271 participates in an acid-induced opening of the epoxide moiety of leukotriene A(4) and formation of a carbocation intermediate. Moreover, Glu-271 appears to act as an N-terminal recognition site and may potentially stabilize the transition-state during turnover of peptides, a property that most likely pertains to all members of the M1 family of zinc aminopeptidases. Hence, Glu-271 is a unique example of an amino acid, which has dual and separate functions in two different catalytic reactions, involving lipid and peptide substrates, respectively.
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Affiliation(s)
- Peter C Rudberg
- Department of Medical Biochemistry and Biophysics, Division of Chemistry II, Karolinska Institutet, S-171 77 Stockholm, Sweden
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