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Xu N, Zuo J, Li C, Gao C, Guo M. Reconstruction and Analysis of a Genome-Scale Metabolic Model of Acinetobacter lwoffii. Int J Mol Sci 2024; 25:9321. [PMID: 39273268 PMCID: PMC11395192 DOI: 10.3390/ijms25179321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 07/31/2024] [Accepted: 08/22/2024] [Indexed: 09/15/2024] Open
Abstract
Acinetobacter lwoffii is widely considered to be a harmful bacterium that is resistant to medicines and disinfectants. A. lwoffii NL1 degrades phenols efficiently and shows promise as an aromatic compound degrader in antibiotic-contaminated environments. To gain a comprehensive understanding of A. lwoffii, the first genome-scale metabolic model of A. lwoffii was constructed using semi-automated and manual methods. The iNX811 model, which includes 811 genes, 1071 metabolites, and 1155 reactions, was validated using 39 unique carbon and nitrogen sources. Genes and metabolites critical for cell growth were analyzed, and 12 essential metabolites (mainly in the biosynthesis and metabolism of glycan, lysine, and cofactors) were identified as antibacterial drug targets. Moreover, to explore the metabolic response to phenols, metabolic flux was simulated by integrating transcriptomics, and the significantly changed metabolism mainly included central carbon metabolism, along with some transport reactions. In addition, the addition of substances that effectively improved phenol degradation was predicted and validated using the model. Overall, the reconstruction and analysis of model iNX811 helped to study the antimicrobial systems and biodegradation behavior of A. lwoffii.
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Affiliation(s)
- Nan Xu
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Jiaojiao Zuo
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Chenghao Li
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Cong Gao
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Minliang Guo
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
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2
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Korshoj LE, Kielian T. Bacterial single-cell RNA sequencing captures biofilm transcriptional heterogeneity and differential responses to immune pressure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601229. [PMID: 38979200 PMCID: PMC11230364 DOI: 10.1101/2024.06.28.601229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Biofilm formation is an important mechanism of survival and persistence for many bacterial pathogens. These multicellular communities contain subpopulations of cells that display vast metabolic and transcriptional diversity along with high recalcitrance to antibiotics and host immune defenses. Investigating the complex heterogeneity within biofilm has been hindered by the lack of a sensitive and high-throughput method to assess stochastic transcriptional activity and regulation between bacterial subpopulations, which requires single-cell resolution. We have developed an optimized bacterial single-cell RNA sequencing method, BaSSSh-seq, to study Staphylococcus aureus diversity during biofilm growth and transcriptional adaptations following immune cell exposure. We validated the ability of BaSSSh-seq to capture extensive transcriptional heterogeneity during biofilm compared to planktonic growth. Application of new computational tools revealed transcriptional regulatory networks across the heterogeneous biofilm subpopulations and identification of gene sets that were associated with a trajectory from planktonic to biofilm growth. BaSSSh-seq also detected alterations in biofilm metabolism, stress response, and virulence that were tailored to distinct immune cell populations. This work provides an innovative platform to explore biofilm dynamics at single-cell resolution, unlocking the potential for identifying biofilm adaptations to environmental signals and immune pressure.
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3
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Ren Z, Yu J, Du J, Zhang Y, Hamushan M, Jiang F, Zhang F, Wang B, Tang J, Shen H, Han P. A General Map of Transcriptional Expression of Virulence, Metabolism, and Biofilm Formation Adaptive Changes of Staphylococcus aureus When Exposed to Different Antimicrobials. Front Microbiol 2022; 13:825041. [PMID: 35783396 PMCID: PMC9247510 DOI: 10.3389/fmicb.2022.825041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Biofilm formation of Staphylococcus aureus is the major cause of implant-associated infections (IAIs). Antimicrobial treatment is one of the most effective therapeutic options for S. aureus infections. However, it can also lead to adaptive transcriptomic changes due to extreme selective pressure, which may increase the risk of antimicrobial resistance. To study the transcriptional changes in S. aureus upon exposure to antimicrobial agents, we obtained expression profiles of S. aureus treated with six antimicrobials (flucloxacillin, vancomycin, ciprofloxacin, clindamycin, erythromycin, and linezolid, n = 6 for each group). We also included an untreated control group (n = 8) downloaded from the Gene Expression Omnibus (GEO) database (GSE70043, GSE56100) for integrated bioinformatic analyses. We identified 82 (44 up, 38 down) and 53 (17 up, 36 down) differentially expressed genes (DEGs) in logarithmic and stationary phases, respectively. When exposed to different antimicrobial agents, we found that manganese import system genes and immune response gene sbi (immunoglobulin G-binding protein Sbi) were upregulated in S. aureus at all stages. During the logarithmic phase, we observed adaptive transcriptomic changes in S. aureus mainly in the stability of protein synthesis, adhesion, and biofilm formation. In the stationary phase, we observed a downregulation in genes related to amino biosynthesis, ATP synthesis, and DNA replication. We verified these results by qPCR. Importantly, these results could help our understanding of the molecular mechanisms underlying the proliferation and antimicrobial resistance of S. aureus.
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Affiliation(s)
- Zun Ren
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Jinlong Yu
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Jiafei Du
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Yubo Zhang
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Musha Hamushan
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Feng Jiang
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Feiyang Zhang
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Boyong Wang
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Jin Tang
- Department of Clinical Laboratory, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- *Correspondence: Jin Tang,
| | - Hao Shen
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Department of Orthopedics, Shanghai Sixth People’s Hospital Fujian, Jinjiang, China
- Hao Shen,
| | - Pei Han
- Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Pei Han,
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4
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Schmitz RA, Dietl A, Müller M, Berben T, Op den Camp HJM, Barends TRM. Structure of the 4-hydroxy-tetrahydrodipicolinate synthase from the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV and the phylogeny of the aminotransferase pathway. Acta Crystallogr F Struct Biol Commun 2020; 76:199-208. [PMID: 32356521 PMCID: PMC7193512 DOI: 10.1107/s2053230x20005294] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/15/2020] [Indexed: 11/10/2022] Open
Abstract
The enzyme 4-hydroxy-tetrahydrodipicolinate synthase (DapA) is involved in the production of lysine and precursor molecules for peptidoglycan synthesis. In a multistep reaction, DapA converts pyruvate and L-aspartate-4-semialdehyde to 4-hydroxy-2,3,4,5-tetrahydrodipicolinic acid. In many organisms, lysine binds allosterically to DapA, causing negative feedback, thus making the enzyme an important regulatory component of the pathway. Here, the 2.1 Å resolution crystal structure of DapA from the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV is reported. The enzyme crystallized as a contaminant of a protein preparation from native biomass. Genome analysis reveals that M. fumariolicum SolV utilizes the recently discovered aminotransferase pathway for lysine biosynthesis. Phylogenetic analyses of the genes involved in this pathway shed new light on the distribution of this pathway across the three domains of life.
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Affiliation(s)
- Rob A. Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Andreas Dietl
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Melanie Müller
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Tom Berben
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Huub J. M. Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525 AJ Nijmegen, The Netherlands
| | - Thomas R. M. Barends
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
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5
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Majdi Yazdi M, Saran S, Mrozowich T, Lehnert C, Patel TR, Sanders DAR, Palmer DRJ. Asparagine-84, a regulatory allosteric site residue, helps maintain the quaternary structure of Campylobacter jejuni dihydrodipicolinate synthase. J Struct Biol 2019; 209:107409. [PMID: 31678256 DOI: 10.1016/j.jsb.2019.107409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/18/2019] [Accepted: 10/28/2019] [Indexed: 02/05/2023]
Abstract
Dihydrodipicolinate synthase (DHDPS) from Campylobacter jejuni is a natively homotetrameric enzyme that catalyzes the first unique reaction of (S)-lysine biosynthesis and is feedback-regulated by lysine through binding to an allosteric site. High-resolution structures of the DHDPS-lysine complex have revealed significant insights into the binding events. One key asparagine residue, N84, makes hydrogen bonds with both the carboxyl and the α-amino group of the bound lysine. We generated two mutants, N84A and N84D, to study the effects of these changes on the allosteric site properties. However, under normal assay conditions, N84A displayed notably lower catalytic activity, and N84D showed no activity. Here we show that these mutations disrupt the quaternary structure of DHDPS in a concentration-dependent fashion, as demonstrated by size-exclusion chromatography, multi-angle light scattering, dynamic light scattering, small-angle X-ray scattering (SAXS) and high-resolution protein crystallography.
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Affiliation(s)
- Mohadeseh Majdi Yazdi
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Sagar Saran
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Tyler Mrozowich
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada
| | - Cheyanne Lehnert
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Trushar R Patel
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada; Li Ka Shing Institute of Virology and DiscoveryLab, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - David A R Sanders
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
| | - David R J Palmer
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
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6
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Impey RE, Panjikar S, Hall CJ, Bock LJ, Sutton JM, Perugini MA, Soares da Costa TP. Identification of two dihydrodipicolinate synthase isoforms from Pseudomonas aeruginosa that differ in allosteric regulation. FEBS J 2019; 287:386-400. [PMID: 31330085 DOI: 10.1111/febs.15014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/12/2019] [Accepted: 07/19/2019] [Indexed: 12/13/2022]
Abstract
Pseudomonas aeruginosa is one of the leading causes of nosocomial infections, accounting for 10% of all hospital-acquired infections. Current antibiotics against P. aeruginosa are becoming increasingly ineffective due to the exponential rise in drug resistance. Thus, there is an urgent need to validate and characterize novel drug targets to guide the development of new classes of antibiotics against this pathogen. One such target is the diaminopimelate (DAP) pathway, which is responsible for the biosynthesis of bacterial cell wall and protein building blocks, namely meso-DAP and lysine. The rate-limiting step of this pathway is catalysed by the enzyme dihydrodipicolinate synthase (DHDPS), typically encoded for in bacteria by a single dapA gene. Here, we show that P. aeruginosa encodes two functional DHDPS enzymes, PaDHDPS1 and PaDHDPS2. Although these isoforms have similar catalytic activities (kcat = 29 s-1 and 44 s-1 for PaDHDPS1 and PaDHDPS2, respectively), they are differentially allosterically regulated by lysine, with only PaDHDPS2 showing inhibition by the end product of the DAP pathway (IC50 = 130 μm). The differences in allostery are attributed to a single amino acid difference in the allosteric binding pocket at position 56. This is the first example of a bacterium that contains multiple bona fide DHDPS enzymes, which differ in allosteric regulation. We speculate that the presence of the two isoforms allows an increase in the metabolic flux through the DAP pathway when required in this clinically important pathogen. DATABASES: PDB ID: 6P90.
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Affiliation(s)
- Rachael E Impey
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Santosh Panjikar
- Australian Synchrotron, ANSTO, Clayton, Australia.,Department of Molecular Biology and Biochemistry, Monash University, Melbourne, Australia
| | - Cody J Hall
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Lucy J Bock
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - J Mark Sutton
- National Infection Service, Public Health England, Porton Down, Salisbury, UK
| | - Matthew A Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Tatiana P Soares da Costa
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
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7
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Atkinson SC, Dogovski C, Wood K, Griffin MDW, Gorman MA, Hor L, Reboul CF, Buckle AM, Wuttke J, Parker MW, Dobson RCJ, Perugini MA. Substrate Locking Promotes Dimer-Dimer Docking of an Enzyme Antibiotic Target. Structure 2018; 26:948-959.e5. [PMID: 29804823 DOI: 10.1016/j.str.2018.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/27/2018] [Accepted: 04/19/2018] [Indexed: 11/19/2022]
Abstract
Protein dynamics manifested through structural flexibility play a central role in the function of biological molecules. Here we explore the substrate-mediated change in protein flexibility of an antibiotic target enzyme, Clostridium botulinum dihydrodipicolinate synthase. We demonstrate that the substrate, pyruvate, stabilizes the more active dimer-of-dimers or tetrameric form. Surprisingly, there is little difference between the crystal structures of apo and substrate-bound enzyme, suggesting protein dynamics may be important. Neutron and small-angle X-ray scattering experiments were used to probe substrate-induced dynamics on the sub-second timescale, but no significant changes were observed. We therefore developed a simple technique, coined protein dynamics-mass spectrometry (ProD-MS), which enables measurement of time-dependent alkylation of cysteine residues. ProD-MS together with X-ray crystallography and analytical ultracentrifugation analyses indicates that pyruvate locks the conformation of the dimer that promotes docking to the more active tetrameric form, offering insight into ligand-mediated stabilization of multimeric enzymes.
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Affiliation(s)
- Sarah C Atkinson
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia
| | - Con Dogovski
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia
| | - Kathleen Wood
- Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael A Gorman
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Lilian Hor
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, La Trobe University, Melbourne, VIC 3086, Australia
| | - Cyril F Reboul
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ashley M Buckle
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Joachim Wuttke
- Juelich Centre for Neutron Science (JCNS), at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Juelich GmbH, Lichtenstrasse 1, Garching 85 747, Germany
| | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Renwick C J Dobson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Private Bag, Christchurch 4800, New Zealand
| | - Matthew A Perugini
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, University of Melbourne, Parkville, VIC 3010, Australia; Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia.
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8
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Desbois S, John UP, Perugini MA. Dihydrodipicolinate synthase is absent in fungi. Biochimie 2018; 152:73-84. [PMID: 29959064 DOI: 10.1016/j.biochi.2018.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 06/21/2018] [Indexed: 02/07/2023]
Abstract
The class I aldolase dihydrodipicolinate synthase (DHDPS) catalyzes the first committed step of the diaminopimelate (DAP) lysine biosynthesis pathway in bacteria, archaea and plants. Despite the existence, in databases, of numerous fungal sequences annotated as DHDPS, its presence in fungi has been the subject of contradictory claims. We report the characterization of DHDPS candidates from fungi. Firstly, the putative DHDPS from Coccidioides immitis (PDB ID: 3QFE) was shown to have negligible enzyme activity. Sequence analysis of 3QFE showed that three out of the seven amino acid residues critical for DHDPS activity are absent; however, exact matches to catalytic residues from two other class I aldolases, 2-keto-3-deoxygluconate aldolase (KDGA), and 4-hydroxy-2-oxoglutarate aldolase (HOGA), were identified. The presence of both KDGA and HOGA activity in 3QFE was confirmed in vitro using enzyme assays, the first report of such dual activity. Subsequent analyses of all publically available fungal sequences revealed that no entry contains all seven residues important for DHDPS function. The candidate with the highest number of identities (6 of 7), KIW77228 from Fonsecaea pedrosoi, was shown to have trace DHDPS activity in vitro, partially restored by substitution of the seventh critical residue, and to be incapable of complementing DHDPS-deficient E. coli cells. Combined with the presence of all seven sequences for the alternative α-aminoadipate (AAA) lysine biosynthesis pathway in C. immitis and F. pedrosoi, we believe that DHDPS and the DAP pathway are absent in fungi, and further, that robust informed methods for annotating genes need to be implemented.
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Affiliation(s)
- Sebastien Desbois
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, VIC, 3086, Australia
| | - Ulrik P John
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, VIC, 3086, Australia; Agriculture Victoria Research, Department of Economic Development, Jobs, Transport and Resources, AgriBio, La Trobe University, VIC, 3086, Australia
| | - Matthew A Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, VIC, 3086, Australia.
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9
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Soares da Costa TP, Abbott BM, Gendall AR, Panjikar S, Perugini MA. Molecular evolution of an oligomeric biocatalyst functioning in lysine biosynthesis. Biophys Rev 2018; 10:153-162. [PMID: 29204887 PMCID: PMC5899710 DOI: 10.1007/s12551-017-0350-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 11/14/2017] [Indexed: 12/28/2022] Open
Abstract
Dihydrodipicolinate synthase (DHDPS) is critical to the production of lysine through the diaminopimelate (DAP) pathway. Elucidation of the function, regulation and structure of this key class I aldolase has been the focus of considerable study in recent years, given that the dapA gene encoding DHDPS has been found to be essential to bacteria and plants. Allosteric inhibition by lysine is observed for DHDPS from plants and some bacterial species, the latter requiring a histidine or glutamate at position 56 (Escherichia coli numbering) over a basic amino acid. Structurally, two DHDPS monomers form the active site, which binds pyruvate and (S)-aspartate β-semialdehyde, with most dimers further dimerising to form a tetrameric arrangement around a solvent-filled centre cavity. The architecture and behaviour of these dimer-of-dimers is explored in detail, including biophysical studies utilising analytical ultracentrifugation, small-angle X-ray scattering and macromolecular crystallography that show bacterial DHDPS tetramers adopt a head-to-head quaternary structure, compared to the back-to-back arrangement observed for plant DHDPS enzymes. Finally, the potential role of pyruvate in providing substrate-mediated stabilisation of DHDPS is considered.
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Affiliation(s)
- Tatiana P Soares da Costa
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Belinda M Abbott
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Anthony R Gendall
- Department of Animal, Plant and Soil Sciences, AgriBio, Centre for AgriBiosciences, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Santosh Panjikar
- Australian Synchrotron, Clayton, Melbourne, VIC, 3168, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, VIC, 3800, Australia
| | - Matthew A Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia.
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10
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Soares da Costa TP, Patel M, Desbois S, Gupta R, Faou P, Perugini MA. Identification of a dimeric KDG aldolase from
Agrobacterium tumefaciens. Proteins 2017; 85:2058-2065. [DOI: 10.1002/prot.25359] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/17/2017] [Accepted: 07/24/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Tatiana P. Soares da Costa
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityMelbourne Victoria Australia
| | - Madhvi Patel
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityMelbourne Victoria Australia
| | - Sebastien Desbois
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityMelbourne Victoria Australia
| | - Ruchi Gupta
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityMelbourne Victoria Australia
| | - Pierre Faou
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityMelbourne Victoria Australia
| | - Matthew A. Perugini
- Department of Biochemistry and GeneticsLa Trobe Institute for Molecular Science, La Trobe UniversityMelbourne Victoria Australia
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11
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Grant Pearce F, Hudson AO, Loomes K, Dobson RCJ. Dihydrodipicolinate Synthase: Structure, Dynamics, Function, and Evolution. Subcell Biochem 2017; 83:271-289. [PMID: 28271480 DOI: 10.1007/978-3-319-46503-6_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Enzymes are usually comprised of multiple subunits and more often than not they are made up of identical subunits. In this review we examine lysine biosynthesis and focus on the enzyme dihydrodipicolinate synthase in terms of its structure, function and the evolution of its varied number of subunits (quaternary structure). Dihydrodipicolinate synthase is the first committed step in the biosynthesis of lysine, which occurs naturally in plants, bacteria, archaea and fungi, but is not synthesized in mammals. In bacteria, there have been four separate pathways identified from tetrahydrodipicolinate to meso-diaminopimelate, which is the immediate precursor to lysine. Dihydrodipicolinate synthases from many bacterial and plant species have been structurally characterised and the results show considerable variability with respect to their quaternary structure, hinting at their evolution. The oligomeric state of the enzyme plays a key role, both in catalysis and in the allosteric regulation of the enzyme by lysine. While most bacteria and plants have tetrameric enzymes, where the structure of the dimeric building blocks is conserved, the arrangement of the dimers differs. We also review a key development in the field, namely the discovery of a human dihydrodipicolinate synthase-like enzyme, now known as 4-hydroxy-2-oxoglutarate aldolase . This discovery complicates the rationale underpinning drug development against bacterial dihydrodipicolinate synthases, since genetic errors in 4-hydroxy-2-oxoglutarate aldolase cause the disease Primary Hyperoxaluria Type 3 and therefore compounds that are geared towards the inhibition of bacterial dihydrodipicolinate synthase may be toxic to mammalian cells.
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Affiliation(s)
- F Grant Pearce
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand
| | - André O Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | - Kerry Loomes
- School of Biological Sciences & Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Renwick C J Dobson
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, 8041, New Zealand.
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, VIC, 3010, Australia.
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12
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Christensen JB, Soares da Costa TP, Faou P, Pearce FG, Panjikar S, Perugini MA. Structure and Function of Cyanobacterial DHDPS and DHDPR. Sci Rep 2016; 6:37111. [PMID: 27845445 PMCID: PMC5109050 DOI: 10.1038/srep37111] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/25/2016] [Indexed: 11/21/2022] Open
Abstract
Lysine biosynthesis in bacteria and plants commences with a condensation reaction catalysed by dihydrodipicolinate synthase (DHDPS) followed by a reduction reaction catalysed by dihydrodipicolinate reductase (DHDPR). Interestingly, both DHDPS and DHDPR exist as different oligomeric forms in bacteria and plants. DHDPS is primarily a homotetramer in all species, but the architecture of the tetramer differs across kingdoms. DHDPR also exists as a tetramer in bacteria, but has recently been reported to be dimeric in plants. This study aimed to characterise for the first time the structure and function of DHDPS and DHDPR from cyanobacteria, which is an evolutionary important phylum that evolved at the divergence point between bacteria and plants. We cloned, expressed and purified DHDPS and DHDPR from the cyanobacterium Anabaena variabilis. The recombinant enzymes were shown to be folded by circular dichroism spectroscopy, enzymatically active employing the quantitative DHDPS-DHDPR coupled assay, and form tetramers in solution using analytical ultracentrifugation. Crystal structures of DHDPS and DHDPR from A. variabilis were determined at 1.92 Å and 2.83 Å, respectively, and show that both enzymes adopt the canonical bacterial tetrameric architecture. These studies indicate that the quaternary structure of bacterial and plant DHDPS and DHDPR diverged after cyanobacteria evolved.
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Affiliation(s)
- Janni B. Christensen
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - T. P. Soares da Costa
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Pierre Faou
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - F. Grant Pearce
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch 8140, New Zealand
| | - Santosh Panjikar
- Australian Synchrotron, Clayton, Victoria 3168, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Matthew A. Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
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13
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Shrivastava P, Navratna V, Silla Y, Dewangan RP, Pramanik A, Chaudhary S, Rayasam G, Kumar A, Gopal B, Ramachandran S. Inhibition of Mycobacterium tuberculosis dihydrodipicolinate synthase by alpha-ketopimelic acid and its other structural analogues. Sci Rep 2016; 6:30827. [PMID: 27501775 PMCID: PMC4977564 DOI: 10.1038/srep30827] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 07/11/2016] [Indexed: 11/09/2022] Open
Abstract
The Mycobacterium tuberculosis dihydrodipicolinate synthase (Mtb-dapA) is an essential gene. Mtb-DapA catalyzes the aldol condensation between pyruvate and L-aspartate-beta-semialdehyde (ASA) to yield dihydrodipicolinate. In this work we tested the inhibitory effects of structural analogues of pyruvate on recombinant Mtb-DapA (Mtb-rDapA) using a coupled assay with recombinant dihydrodipicolinate reductase (Mtb-rDapB). Alpha-ketopimelic acid (α-KPA) showed maximum inhibition of 88% and IC50 of 21 μM in the presence of pyruvate (500 μM) and ASA (400 μM). Competition experiments with pyruvate and ASA revealed competition of α-KPA with pyruvate. Liquid chromatography-mass spectrometry (LC-MS) data with multiple reaction monitoring (MRM) showed that the relative abundance peak of final product, 2,3,4,5-tetrahydrodipicolinate, was decreased by 50%. Thermal shift assays showed 1 °C Tm shift of Mtb-rDapA upon binding α-KPA. The 2.4 Å crystal structure of Mtb-rDapA-α-KPA complex showed the interaction of critical residues at the active site with α-KPA. Molecular dynamics simulations over 500 ns of pyruvate docked to Mtb-DapA and of α-KPA-bound Mtb-rDapA revealed formation of hydrogen bonds with pyruvate throughout in contrast to α-KPA. Molecular descriptors analysis showed that ligands with polar surface area of 91.7 Å(2) are likely inhibitors. In summary, α-hydroxypimelic acid and other analogues could be explored further as inhibitors of Mtb-DapA.
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Affiliation(s)
- Priyanka Shrivastava
- Functional Genomics Unit, Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB), South Campus, New Delhi 110025, India
- Academy of Scientific and Innovative Research, CSIR-IGIB South Campus, New Delhi 110025, India
| | - Vikas Navratna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Yumnam Silla
- Biotechnology Group (BIF center), Biological Science & Technology Division (BSTD), CSIR-North-East Institute of Science and Technology (CSIR-NEIST), Jorhat, Assam, 785006, India
| | - Rikeshwer P. Dewangan
- Functional Genomics Unit, Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB), South Campus, New Delhi 110025, India
| | - Atreyi Pramanik
- Functional Genomics Unit, Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB), South Campus, New Delhi 110025, India
| | - Sarika Chaudhary
- Functional Genomics Unit, Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB), South Campus, New Delhi 110025, India
| | - GeethaVani Rayasam
- Open Source Drug Discovery Unit (OSDD), CSIR-IGIB, New Delhi, 110001, India
| | - Anuradha Kumar
- Open Source Drug Discovery Unit (OSDD), CSIR-IGIB, New Delhi, 110001, India
| | | | - Srinivasan Ramachandran
- Functional Genomics Unit, Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology (CSIR-IGIB), South Campus, New Delhi 110025, India
- Academy of Scientific and Innovative Research, CSIR-IGIB South Campus, New Delhi 110025, India
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14
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Soares da Costa TP, Desbois S, Dogovski C, Gorman MA, Ketaren NE, Paxman JJ, Siddiqui T, Zammit LM, Abbott BM, Robins-Browne RM, Parker MW, Jameson GB, Hall NE, Panjikar S, Perugini MA. Structural Determinants Defining the Allosteric Inhibition of an Essential Antibiotic Target. Structure 2016; 24:1282-1291. [PMID: 27427481 DOI: 10.1016/j.str.2016.05.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/22/2016] [Accepted: 05/06/2016] [Indexed: 11/29/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyzes the first committed step in the lysine biosynthesis pathway of bacteria. The pathway can be regulated by feedback inhibition of DHDPS through the allosteric binding of the end product, lysine. The current dogma states that DHDPS from Gram-negative bacteria are inhibited by lysine but orthologs from Gram-positive species are not. The 1.65-Å resolution structure of the Gram-negative Legionella pneumophila DHDPS and the 1.88-Å resolution structure of the Gram-positive Streptococcus pneumoniae DHDPS bound to lysine, together with comprehensive functional analyses, show that this dogma is incorrect. We subsequently employed our crystallographic data with bioinformatics, mutagenesis, enzyme kinetics, and microscale thermophoresis to reveal that lysine-mediated inhibition is not defined by Gram staining, but by the presence of a His or Glu at position 56 (Escherichia coli numbering). This study has unveiled the molecular determinants defining lysine-mediated allosteric inhibition of bacterial DHDPS.
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Affiliation(s)
- Tatiana P Soares da Costa
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Sebastien Desbois
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Con Dogovski
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Michael A Gorman
- St Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Natalia E Ketaren
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jason J Paxman
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia; Australian Synchrotron, Clayton, VIC 3168, Australia
| | - Tanzeela Siddiqui
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Leanne M Zammit
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Belinda M Abbott
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Roy M Robins-Browne
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, VIC 3010, Australia; Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia
| | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia; St Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Geoffrey B Jameson
- Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Nathan E Hall
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Santosh Panjikar
- Australian Synchrotron, Clayton, VIC 3168, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Matthew A Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3086, Australia.
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15
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Gordon SE, Weber DK, Downton MT, Wagner J, Perugini MA. Dynamic Modelling Reveals 'Hotspots' on the Pathway to Enzyme-Substrate Complex Formation. PLoS Comput Biol 2016; 12:e1004811. [PMID: 26967332 PMCID: PMC4788353 DOI: 10.1371/journal.pcbi.1004811] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/12/2016] [Indexed: 11/29/2022] Open
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyzes the first committed step in the diaminopimelate pathway of bacteria, yielding amino acids required for cell wall and protein biosyntheses. The essentiality of the enzyme to bacteria, coupled with its absence in humans, validates DHDPS as an antibacterial drug target. Conventional drug design efforts have thus far been unsuccessful in identifying potent DHDPS inhibitors. Here, we make use of contemporary molecular dynamics simulation and Markov state models to explore the interactions between DHDPS from the human pathogen Staphylococcus aureus and its cognate substrate, pyruvate. Our simulations recover the crystallographic DHDPS-pyruvate complex without a priori knowledge of the final bound structure. The highly conserved residue Arg140 was found to have a pivotal role in coordinating the entry of pyruvate into the active site from bulk solvent, consistent with previous kinetic reports, indicating an indirect role for the residue in DHDPS catalysis. A metastable binding intermediate characterized by multiple points of intermolecular interaction between pyruvate and key DHDPS residue Arg140 was found to be a highly conserved feature of the binding trajectory when comparing alternative binding pathways. By means of umbrella sampling we show that these binding intermediates are thermodynamically metastable, consistent with both the available experimental data and the substrate binding model presented in this study. Our results provide insight into an important enzyme-substrate interaction in atomistic detail that offers the potential to be exploited for the discovery of more effective DHDPS inhibitors and, in a broader sense, dynamic protein-drug interactions. Interactions between proteins and ligands underpin many important biological processes, such as binding of substrates to their cognate enzymes in the process of catalysis. These interactions are complex, often requiring several intermediate steps to fully transition into the bound state. Here, we have used computational simulation to study binding of pyruvate to Dihydrodipicolinate synthase (DHDPS), an enzyme in the bacterial diaminopimelate pathway. In bacteria, such as the human pathogen S. aureus, DHDPS functions to make building blocks necessary for protein and bacterial cell wall biosyntheses. As the enzyme is absent in humans, yet essential for bacterial growth, DHDPS is a valid target for broad-range antibiotics. However, known DHDPS inhibitors show poor potency. One avenue that has not yet been taken into consideration for inhibitor design is the dynamics of DHDPS’s interaction with its reaction substrates (e.g. pyruvate). Using molecular dynamics simulation, we find that pyruvate binding to DHDPS must pass through a transition intermediate ‘hotspot’ in which the substrate is held in place by a dense network of noncovalent bonds. Given that many of the protein residues involved in this interaction are also shared by DHDPS from many pathogenic bacteria, this binding intermediate ‘hotspot’ may help in development of better broad-range DHDPS inhibitors.
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Affiliation(s)
- Shane E. Gordon
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- Computational Biophysics, IBM Research - Australia, Carlton, Victoria, Australia
| | - Daniel K. Weber
- Computational Biophysics, IBM Research - Australia, Carlton, Victoria, Australia
| | - Matthew T. Downton
- Computational Biophysics, IBM Research - Australia, Carlton, Victoria, Australia
| | - John Wagner
- Computational Biophysics, IBM Research - Australia, Carlton, Victoria, Australia
| | - Matthew A. Perugini
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- * E-mail:
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16
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Naqvi KF, Staker BL, Dobson RCJ, Serbzhinskiy D, Sankaran B, Myler PJ, Hudson AO. Cloning, expression, purification, crystallization and X-ray diffraction analysis of dihydrodipicolinate synthase from the human pathogenic bacterium Bartonella henselae strain Houston-1 at 2.1 Å resolution. Acta Crystallogr F Struct Biol Commun 2016; 72:2-9. [PMID: 26750477 PMCID: PMC4708043 DOI: 10.1107/s2053230x15023213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/02/2015] [Indexed: 11/10/2022] Open
Abstract
The enzyme dihydrodipicolinate synthase catalyzes the committed step in the synthesis of diaminopimelate and lysine to facilitate peptidoglycan and protein synthesis. Dihydrodipicolinate synthase catalyzes the condensation of L-aspartate 4-semialdehyde and pyruvate to synthesize L-2,3-dihydrodipicolinate. Here, the cloning, expression, purification, crystallization and X-ray diffraction analysis of dihydrodipicolinate synthase from the pathogenic bacterium Bartonella henselae, the causative bacterium of cat-scratch disease, are presented. Protein crystals were grown in conditions consisting of 20%(w/v) PEG 4000, 100 mM sodium citrate tribasic pH 5.5 and were shown to diffract to ∼2.10 Å resolution. They belonged to space group P212121, with unit-cell parameters a = 79.96, b = 106.33, c = 136.25 Å. The final R values were Rr.i.m. = 0.098, Rwork = 0.183, Rfree = 0.233.
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Affiliation(s)
- Kubra F. Naqvi
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, USA
| | - Bart L. Staker
- Seattle Structural Genomics Center for Infectious Disease, USA
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Renwick C. J. Dobson
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Dmitry Serbzhinskiy
- Seattle Structural Genomics Center for Infectious Disease, USA
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Ernest Orlando Lawrence Berkeley National Laboratory, USA
| | - Peter J. Myler
- Seattle Structural Genomics Center for Infectious Disease, USA
- Center for Infectious Disease Research, 307 Westlake Avenue North, Suite 500, Seattle, WA 98109, USA
- Department of Global Health, University of Washington, Seattle, WA 98195, USA
- Department of Biomedical Informatics and Health Education, University of Washington, Seattle, WA 98195, USA
| | - André O. Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623-5603, USA
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17
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Abstract
Here, we review recent studies aimed at defining the importance of quaternary structure to a model oligomeric enzyme, dihydrodipicolinate synthase. This will illustrate the complementary and synergistic outcomes of coupling the techniques of analytical ultracentrifugation with enzyme kinetics, in vitro mutagenesis, macromolecular crystallography, small angle X-ray scattering, and molecular dynamics simulations, to demonstrate the role of subunit self-association in facilitating protein dynamics and enzyme function. This multitechnique approach has yielded new insights into the molecular evolution of protein quaternary structure.
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18
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Crystal structure and in silico studies of dihydrodipicolinate synthase (DHDPS) from Aquifex aeolicus. Extremophiles 2014; 18:973-85. [PMID: 24996798 DOI: 10.1007/s00792-014-0667-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 06/07/2014] [Indexed: 10/25/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS, E.C.4.2.1.52) catalyzes the first committed step in the lysine biosynthetic pathway: the condensation of (S)-aspartate semialdehyde and pyruvate to form (4S)-4-hydroxy-2,3,4,5-tetrahydro-(2S)-dipicolinic acid. Since (S)-lysine biosynthesis does not occur in animals, DHDPS is an attractive target for rational antibiotic and herbicide design. Here, we report the crystal structure of DHDPS from a hyperthermophilic bacterium Aquifex aeolicus (AqDHDPS). L-Lysine is used as an important animal feed additive where the production is at the level of 1.5 million tons per year. The biotechnological manufacture of lysine has been going for more than 50 years which includes over synthesis and reverse engineering of DHDPS. AqDHDPS revealed a unique disulfide linkage which is not conserved in the homologues of AqDHDPS. In silico mutation of C139A and intermolecular ion-pair residues and the subsequent molecular dynamics simulation of the mutants showed that these residues are critical for the stability of AqDHDPS tetramer. MD simulations of AqDHDPS at three different temperatures (303, 363 and 393 K) revealed that the molecule is stable at 363 K. Thus, this structural and in silico study of AqDHDPS likely provides additional details towards the rational and structure-based design of hyper-L-lysine producing bacterial strains.
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19
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Atkinson SC, Hor L, Dogovski C, Dobson RCJ, Perugini MA. Identification of the bona fide DHDPS from a common plant pathogen. Proteins 2014; 82:1869-83. [PMID: 24677246 DOI: 10.1002/prot.24539] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 01/06/2014] [Accepted: 02/13/2014] [Indexed: 11/10/2022]
Abstract
Agrobacterium tumefaciens is a Gram-negative soil-borne bacterium that causes Crown Gall disease in many economically important crops. The absence of a suitable chemical treatment means there is a need to discover new anti-Crown Gall agents and also characterize bona fide drug targets. One such target is dihydrodipicolinate synthase (DHDPS), a homo-tetrameric enzyme that catalyzes the committed step in the metabolic pathway yielding meso-diaminopimelate and lysine. Interestingly, there are 10 putative DHDPS genes annotated in the A. tumefaciens genome, including three whose structures have recently been determined (PDB IDs: 3B4U, 2HMC, and 2R8W). However, we show using quantitative enzyme kinetic assays that nine of the 10 dapA gene products, including 3B4U, 2HMC, and 2R8W, lack DHDPS function in vitro. A sequence alignment showed that the product of the dapA7 gene contains all of the conserved residues known to be important for DHDPS catalysis and allostery. This gene was cloned and the recombinant product expressed and purified. Our studies show that the purified enzyme (i) possesses DHDPS enzyme activity, (ii) is allosterically inhibited by lysine, and (iii) adopts the canonical homo-tetrameric structure in both solution and the crystal state. This study describes for the first time the structure, function and allostery of the bona fide DHDPS from A. tumefaciens, which offers insight into the rational design of pesticide agents for combating Crown Gall disease.
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Affiliation(s)
- Sarah C Atkinson
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, 3010, Australia
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20
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Dogovski C, Gorman MA, Ketaren NE, Praszkier J, Zammit LM, Mertens HD, Bryant G, Yang J, Griffin MDW, Pearce FG, Gerrard JA, Jameson GB, Parker MW, Robins-Browne RM, Perugini MA. From knock-out phenotype to three-dimensional structure of a promising antibiotic target from Streptococcus pneumoniae. PLoS One 2013; 8:e83419. [PMID: 24349508 PMCID: PMC3862839 DOI: 10.1371/journal.pone.0083419] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/13/2013] [Indexed: 11/18/2022] Open
Abstract
Given the rise in drug-resistant Streptococcus pneumoniae, there is an urgent need to discover new antimicrobials targeting this pathogen and an equally urgent need to characterize new drug targets. A promising antibiotic target is dihydrodipicolinate synthase (DHDPS), which catalyzes the rate-limiting step in lysine biosynthesis. In this study, we firstly show by gene knock out studies that S. pneumoniae (sp) lacking the DHDPS gene is unable to grow unless supplemented with lysine-rich media. We subsequently set out to characterize the structure, function and stability of the enzyme drug target. Our studies show that sp-DHDPS is folded and active with a k(cat) = 22 s(-1), K(M)(PYR) = 2.55 ± 0.05 mM and K(M)(ASA) = 0.044 ± 0.003 mM. Thermal denaturation experiments demonstrate sp-DHDPS exhibits an apparent melting temperature (T(M)(app)) of 72 °C, which is significantly greater than Escherichia coli DHDPS (Ec-DHDPS) (T(M)(app) = 59 °C). Sedimentation studies show that sp-DHDPS exists in a dimer-tetramer equilibrium with a K(D)(4→2) = 1.7 nM, which is considerably tighter than its E. coli ortholog (K(D)(4→2) = 76 nM). To further characterize the structure of the enzyme and probe its enhanced stability, we solved the high resolution (1.9 Å) crystal structure of sp-DHDPS (PDB ID 3VFL). The enzyme is tetrameric in the crystal state, consistent with biophysical measurements in solution. Although the sp-DHDPS and Ec-DHDPS active sites are almost identical, the tetramerization interface of the s. pneumoniae enzyme is significantly different in composition and has greater buried surface area (800 Å(2)) compared to its E. coli counterpart (500 Å(2)). This larger interface area is consistent with our solution studies demonstrating that sp-DHDPS is considerably more thermally and thermodynamically stable than Ec-DHDPS. Our study describe for the first time the knock-out phenotype, solution properties, stability and crystal structure of DHDPS from S. pneumoniae, a promising antimicrobial target.
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Affiliation(s)
- Con Dogovski
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - Michael A. Gorman
- St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Natalia E. Ketaren
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - Judy Praszkier
- Department of Microbiology & Immunology, University of Melbourne, Victoria, Australia
| | - Leanne M. Zammit
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | | | - Gary Bryant
- School of Applied Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Ji Yang
- Department of Microbiology & Immunology, University of Melbourne, Victoria, Australia
| | - Michael D. W. Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - F. Grant Pearce
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Juliet A. Gerrard
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Callaghan Innovation, Lower Hutt, New Zealand
| | - Geoffrey B. Jameson
- Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Michael W. Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
- St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Roy M. Robins-Browne
- Department of Microbiology & Immunology, University of Melbourne, Victoria, Australia
| | - Matthew A. Perugini
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
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21
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Navratna V, Gopal B. Crystallization and preliminary X-ray diffraction studies of Staphylococcus aureus homoserine dehydrogenase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1216-9. [PMID: 24192352 PMCID: PMC3818036 DOI: 10.1107/s1744309113025803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 09/18/2013] [Indexed: 11/10/2022]
Abstract
Staphylococcus aureus is a Gram-positive nosocomial pathogen. The prevalence of multidrug-resistant S. aureus strains in both hospital and community settings makes it imperative to characterize new drug targets to combat S. aureus infections. In this context, enzymes involved in cell-wall maintenance and essential amino-acid biosynthesis are significant drug targets. Homoserine dehydrogenase (HSD) is an oxidoreductase that is involved in the reversible conversion of L-aspartate semialdehyde to L-homoserine in a dinucleotide cofactor-dependent reduction reaction. HSD is thus a crucial intermediate enzyme linked to the biosynthesis of several essential amino acids such as lysine, methionine, isoleucine and threonine.
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Affiliation(s)
- Vikas Navratna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560 012, India
| | - Balasubramanian Gopal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560 012, India
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22
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Siddiqui T, Paxman JJ, Dogovski C, Panjikar S, Perugini MA. Cloning to crystallization of dihydrodipicolinate synthase from the intracellular pathogen Legionella pneumophila. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1177-81. [PMID: 24100576 PMCID: PMC3792684 DOI: 10.1107/s1744309113024639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 09/03/2013] [Indexed: 11/11/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyses the rate-limiting step in the biosynthesis of meso-diaminopimelate and lysine. Here, the cloning, expression, purification and crystallization of DHDPS from the intracellular pathogen Legionella pneumophila are described. Crystals grown in the presence of high-molecular-weight PEG precipitant and magnesium chloride were found to diffract beyond 1.65 Å resolution. The crystal lattice belonged to the hexagonal space group P6₁22, with unit-cell parameters a=b=89.31, c=290.18 Å, and contained two molecules in the asymmetric unit. The crystal structure was determined by molecular replacement using a single chain of Pseudomonas aeruginosa DHDPS as the search model.
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Affiliation(s)
- Tanzeela Siddiqui
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
| | | | - Con Dogovski
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
| | - Santosh Panjikar
- Australian Synchrotron, Clayton, VIC 3168, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, VIC 3800, Australia
| | - Matthew A. Perugini
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
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23
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Atkinson SC, Dogovski C, Downton MT, Czabotar PE, Dobson RCJ, Gerrard JA, Wagner J, Perugini MA. Structural, kinetic and computational investigation of Vitis vinifera DHDPS reveals new insight into the mechanism of lysine-mediated allosteric inhibition. PLANT MOLECULAR BIOLOGY 2013; 81:431-446. [PMID: 23354837 DOI: 10.1007/s11103-013-0014-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 01/15/2013] [Indexed: 06/01/2023]
Abstract
Lysine is one of the most limiting amino acids in plants and its biosynthesis is carefully regulated through inhibition of the first committed step in the pathway catalyzed by dihydrodipicolinate synthase (DHDPS). This is mediated via a feedback mechanism involving the binding of lysine to the allosteric cleft of DHDPS. However, the precise allosteric mechanism is yet to be defined. We present a thorough enzyme kinetic and thermodynamic analysis of lysine inhibition of DHDPS from the common grapevine, Vitis vinifera (Vv). Our studies demonstrate that lysine binding is both tight (relative to bacterial DHDPS orthologs) and cooperative. The crystal structure of the enzyme bound to lysine (2.4 Å) identifies the allosteric binding site and clearly shows a conformational change of several residues within the allosteric and active sites. Molecular dynamics simulations comparing the lysine-bound (PDB ID 4HNN) and lysine free (PDB ID 3TUU) structures show that Tyr132, a key catalytic site residue, undergoes significant rotational motion upon lysine binding. This suggests proton relay through the catalytic triad is attenuated in the presence of lysine. Our study reveals for the first time the structural mechanism for allosteric inhibition of DHDPS from the common grapevine.
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Affiliation(s)
- Sarah C Atkinson
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
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24
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Atkinson SC, Dogovski C, Dobson RCJ, Perugini MA. Cloning, expression, purification and crystallization of dihydrodipicolinate synthase from Agrobacterium tumefaciens. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1040-7. [PMID: 22949190 PMCID: PMC3433193 DOI: 10.1107/s1744309112033052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 07/20/2012] [Indexed: 11/10/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyzes the first committed step of the lysine-biosynthesis pathway in bacteria, plants and some fungi. This study describes the cloning, expression, purification and crystallization of DHDPS (NP_354047.1) from the plant pathogen Agrobacterium tumefaciens (AgT-DHDPS). Enzyme-kinetics studies demonstrate that AgT-DHDPS possesses DHDPS activity in vitro. Crystals of AgT-DHDPS were grown in the unliganded form and in forms with substrate bound and with substrate plus allosteric inhibitor (lysine) bound. X-ray diffraction data sets were subsequently collected to a maximum resolution of 1.40 Å. Determination of the structure with and without substrate and inhibitor will offer insight into the design of novel pesticide agents.
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Affiliation(s)
- Sarah C. Atkinson
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria 3010, Australia
| | - Con Dogovski
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Renwick C. J. Dobson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria 3010, Australia
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Matthew A. Perugini
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria 3010, Australia
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25
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Atkinson SC, Dogovski C, Downton MT, Pearce FG, Reboul CF, Buckle AM, Gerrard JA, Dobson RCJ, Wagner J, Perugini MA. Crystal, solution and in silico structural studies of dihydrodipicolinate synthase from the common grapevine. PLoS One 2012; 7:e38318. [PMID: 22761676 PMCID: PMC3382604 DOI: 10.1371/journal.pone.0038318] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 05/08/2012] [Indexed: 11/22/2022] Open
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyzes the rate limiting step in lysine biosynthesis in bacteria and plants. The structure of DHDPS has been determined from several bacterial species and shown in most cases to form a homotetramer or dimer of dimers. However, only one plant DHDPS structure has been determined to date from the wild tobacco species, Nicotiana sylvestris (Blickling et al. (1997) J. Mol. Biol. 274, 608-621). Whilst N. sylvestris DHDPS also forms a homotetramer, the plant enzyme adopts a 'back-to-back' dimer of dimers compared to the 'head-to-head' architecture observed for bacterial DHDPS tetramers. This raises the question of whether the alternative quaternary architecture observed for N. sylvestris DHDPS is common to all plant DHDPS enzymes. Here, we describe the structure of DHDPS from the grapevine plant, Vitis vinifera, and show using analytical ultracentrifugation, small-angle X-ray scattering and X-ray crystallography that V. vinifera DHDPS forms a 'back-to-back' homotetramer, consistent with N. sylvestris DHDPS. This study is the first to demonstrate using both crystal and solution state measurements that DHDPS from the grapevine plant adopts an alternative tetrameric architecture to the bacterial form, which is important for optimizing protein dynamics as suggested by molecular dynamics simulations reported in this study.
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Affiliation(s)
- Sarah C. Atkinson
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Con Dogovski
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Matthew T. Downton
- IBM Research Collaboratory for Life Sciences-Melbourne, Victorian Life Sciences Computation Initiative, Carlton, Australia
| | - F. Grant Pearce
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Cyril F. Reboul
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- ARC Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Victoria, Australia
| | - Ashley M. Buckle
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Juliet A. Gerrard
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Renwick C. J. Dobson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - John Wagner
- IBM Research Collaboratory for Life Sciences-Melbourne, Victorian Life Sciences Computation Initiative, Carlton, Australia
| | - Matthew A. Perugini
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
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26
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Schnell R, Oehlmann W, Sandalova T, Braun Y, Huck C, Maringer M, Singh M, Schneider G. Tetrahydrodipicolinate N-succinyltransferase and dihydrodipicolinate synthase from Pseudomonas aeruginosa: structure analysis and gene deletion. PLoS One 2012; 7:e31133. [PMID: 22359568 PMCID: PMC3281039 DOI: 10.1371/journal.pone.0031133] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/03/2012] [Indexed: 11/19/2022] Open
Abstract
The diaminopimelic acid pathway of lysine biosynthesis has been suggested to provide attractive targets for the development of novel antibacterial drugs. Here we report the characterization of two enzymes from this pathway in the human pathogen Pseudomonas aeruginosa, utilizing structural biology, biochemistry and genetics. We show that tetrahydrodipicolinate N-succinyltransferase (DapD) from P. aeruginosa is specific for the L-stereoisomer of the amino substrate L-2-aminopimelate, and its D-enantiomer acts as a weak inhibitor. The crystal structures of this enzyme with L-2-aminopimelate and D-2-aminopimelate, respectively, reveal that both compounds bind at the same site of the enzyme. Comparison of the binding interactions of these ligands in the enzyme active site suggests misalignment of the amino group of D-2-aminopimelate for nucleophilic attack on the succinate moiety of the co-substrate succinyl-CoA as the structural basis of specificity and inhibition. P. aeruginosa mutants where the dapA gene had been deleted were viable and able to grow in a mouse lung infection model, suggesting that DapA is not an optimal target for drug development against this organism. Structure-based sequence alignments, based on the DapA crystal structure determined to 1.6 Å resolution revealed the presence of two homologues, PA0223 and PA4188, in P. aeruginosa that could substitute for DapA in the P. aeruginosa PAO1ΔdapA mutant. In vitro experiments using recombinant PA0223 protein could however not detect any DapA activity.
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Affiliation(s)
- Robert Schnell
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Wulf Oehlmann
- LIONEX Diagnostics and Therapeutics, Braunschweig, Germany
| | - Tatyana Sandalova
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Yvonne Braun
- LIONEX Diagnostics and Therapeutics, Braunschweig, Germany
| | | | | | - Mahavir Singh
- LIONEX Diagnostics and Therapeutics, Braunschweig, Germany
- * E-mail: (MS); (GS)
| | - Gunter Schneider
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (MS); (GS)
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27
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Atkinson SC, Dogovski C, Newman J, Dobson RCJ, Perugini MA. Cloning, expression, purification and crystallization of dihydrodipicolinate synthase from the grapevine Vitis vinifera. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1537-41. [PMID: 22139160 PMCID: PMC3232133 DOI: 10.1107/s1744309111038395] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 09/19/2011] [Indexed: 11/11/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyses the first committed step of the lysine-biosynthesis pathway in bacteria, plants and some fungi. This study describes the cloning, expression, purification and crystallization of DHDPS from the grapevine Vitis vinifera (Vv-DHDPS). Following in-drop cleavage of the hexahistidine tag, cocrystals of Vv-DHDPS with the substrate pyruvate were grown in 0.1 M Bis-Tris propane pH 8.2, 0.2 M sodium bromide, 20%(w/v) PEG 3350. X-ray diffraction data in space group P1 at a resolution of 2.2 Å are presented. Preliminary diffraction data analysis indicated the presence of eight molecules per asymmetric unit (V(M) = 2.55 Å(3) Da(-1), 52% solvent content). The pending crystal structure of Vv-DHDPS will provide insight into the molecular evolution in quaternary structure of DHDPS enzymes.
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Affiliation(s)
- Sarah C. Atkinson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Con Dogovski
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Janet Newman
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Renwick C. J. Dobson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Matthew A. Perugini
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
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28
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Griffin MDW, Billakanti JM, Gerrard JA, Dobson RCJ, Pearce FG. Crystallization and preliminary X-ray diffraction analysis of dihydrodipicolinate synthase 2 from Arabidopsis thaliana. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1386-90. [PMID: 22102238 PMCID: PMC3212457 DOI: 10.1107/s1744309111033276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 08/16/2011] [Indexed: 11/10/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS; EC 4.2.1.52) catalyzes the first committed step of the lysine-biosynthetic pathway in plants and bacteria. Since (S)-lysine biosynthesis does not occur in animals, DHDPS is an attractive target for rational antibiotic and herbicide design. Here, the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of DHDPS2 from Arabidopsis thaliana are reported. Diffraction-quality protein crystals belonged to space group P2(1)2(1)2.
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Affiliation(s)
- Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
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29
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Proteomics of early and late cold shock stress on thermophilic bacterium, Thermus sp. GH5. J Proteomics 2011; 74:2100-11. [DOI: 10.1016/j.jprot.2011.05.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 05/18/2011] [Accepted: 05/25/2011] [Indexed: 11/19/2022]
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30
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Evans G, Schuldt L, Griffin MDW, Devenish SRA, Grant Pearce F, Perugini MA, Dobson RCJ, Jameson GB, Weiss MS, Gerrard JA. A tetrameric structure is not essential for activity in dihydrodipicolinate synthase (DHDPS) from Mycobacterium tuberculosis. Arch Biochem Biophys 2011; 512:154-9. [PMID: 21672512 DOI: 10.1016/j.abb.2011.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 05/19/2011] [Accepted: 05/20/2011] [Indexed: 11/19/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) is a validated antibiotic target for which a new approach to inhibitor design has been proposed: disrupting native tetramer formation by targeting the dimer-dimer interface. In this study, rational design afforded a variant of Mycobacterium tuberculosis, Mtb-DHDPS-A204R, with disrupted quaternary structure. X-ray crystallography (at a resolution of 2.1Å) revealed a dimeric protein with an identical fold and active-site structure to the tetrameric wild-type enzyme. Analytical ultracentrifugation confirmed the dimeric structure in solution, yet the dimeric mutant has similar activity to the wild-type enzyme. Although the affinity for both substrates was somewhat decreased, the high catalytic competency of the enzyme was surprising in the light of previous results showing that dimeric variants of the Escherichia coli and Bacillus anthracis DHDPS enzymes have dramatically reduced activity compared to their wild-type tetrameric counterparts. These results suggest that Mtb-DHDPS-A204R is similar to the natively dimeric enzyme from Staphylococcus aureus, and highlight our incomplete understanding of the role played by oligomerisation in relating protein structure and function.
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Affiliation(s)
- Genevieve Evans
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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31
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Wubben JM, Dogovski C, Dobson RCJ, Codd R, Gerrard JA, Parker MW, Perugini MA. Cloning, expression, purification and crystallization of dihydrodipicolinate synthase from the psychrophile Shewanella benthica. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1511-6. [PMID: 21045309 PMCID: PMC3001662 DOI: 10.1107/s1744309110036791] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 09/14/2010] [Indexed: 11/10/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) is an oligomeric enzyme that catalyzes the first committed step of the lysine-biosynthesis pathway in plants and bacteria, which yields essential building blocks for cell-wall and protein synthesis. DHDPS is therefore of interest to drug-discovery research as well as to studies that probe the importance of quaternary structure to protein function, stability and dynamics. Accordingly, DHDPS from the psychrophilic (cold-dwelling) organism Shewanella benthica (Sb-DHDPS) was cloned, expressed, purified and crystallized. The best crystals of Sb-DHDPS were grown in 200 mM ammonium sulfate, 100 mM bis-tris pH 5.0-6.0, 23-26%(w/v) PEG 3350, 0.02%(w/v) sodium azide and diffracted to beyond 2.5 Å resolution. Processing of diffraction data to 2.5 Å resolution resulted in a unit cell with space group P2(1)2(1)2(1) and dimensions a = 73.1, b = 84.0, c = 143.7 Å. These studies of the first DHDPS enzyme to be characterized from a bacterial psychrophile will provide insight into the molecular evolution of enzyme structure and dynamics.
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Affiliation(s)
- Jacinta M. Wubben
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Con Dogovski
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Renwick C. J. Dobson
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Rachel Codd
- School of Medical Sciences (Pharmacology) and Bosch Institute, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Juliet A. Gerrard
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Michael W. Parker
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
- St Vincents Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Matthew A. Perugini
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
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32
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Disruption of quaternary structure in Escherichia coli dihydrodipicolinate synthase (DHDPS) generates a functional monomer that is no longer inhibited by lysine. Arch Biochem Biophys 2010; 503:202-6. [PMID: 20709017 DOI: 10.1016/j.abb.2010.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 08/07/2010] [Accepted: 08/10/2010] [Indexed: 11/22/2022]
Abstract
Escherichia coli dihydrodipicolinate synthase (DHDPS, E.C. 4.2.1.52), a natively homotetrameric enzyme was converted to a monomeric species through the introduction of destabilising interactions at two different subunit interfaces allowing exploration of the roles of the quaternary structure in affecting catalytic competency. The double mutant DHDPS-L197D/Y107W displays gel filtration characteristics consistent with a single non-interacting monomeric species, which was confirmed by sedimentary velocity experiments. This monomer was shown to be catalytically active, but with reduced catalytic efficiency (k(cat)=9.8±0.5s(-1)), displaying 8% of the specific activity of the wild-type enzyme. The Michaelis constants for the substrates pyruvate and for (S)-aspartate semialdehyde increased by an order of magnitude, indicating that quaternary structure plays a significant role in substrate specificity. This monomeric species exhibited an enhanced propensity for aggregation and inactivation, indicating that whilst the oligomerization is not an intrinsic criterion for catalysis, higher oligomeric forms may benefit from both increased catalytic efficiency and diminished aggregation propensity. Furthermore, allosteric inhibition by (S)-lysine was abolished for DHDPS-L197D/Y107W, confirming the importance of the dimeric unit as the minimal functional assembly for efficient (S)-lysine binding.
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33
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Soares da Costa TP, Muscroft-Taylor AC, Dobson RCJ, Devenish SRA, Jameson GB, Gerrard JA. How essential is the ‘essential’ active-site lysine in dihydrodipicolinate synthase? Biochimie 2010; 92:837-45. [PMID: 20353808 DOI: 10.1016/j.biochi.2010.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 03/08/2010] [Indexed: 11/15/2022]
Affiliation(s)
- Tatiana P Soares da Costa
- Biomolecular Interaction Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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34
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Griffin MD, Dobson RC, Gerrard JA, Perugini MA. Exploring the dihydrodipicolinate synthase tetramer: How resilient is the dimer–dimer interface? Arch Biochem Biophys 2010; 494:58-63. [DOI: 10.1016/j.abb.2009.11.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 11/10/2009] [Accepted: 11/10/2009] [Indexed: 11/15/2022]
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35
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Sibarani NE, Gorman MA, Dogovski C, Parker MW, Perugini MA. Crystallization of dihydrodipicolinate synthase from a clinical isolate of Streptococcus pneumoniae. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 66:32-6. [PMID: 20057065 DOI: 10.1107/s174430910904771x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Accepted: 11/11/2009] [Indexed: 11/10/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS; EC 4.2.1.52) catalyzes the rate-limiting step in the (S)-lysine biosynthesis pathway of bacteria and plants. Here, the cloning of the DHDPS gene from a clinical isolate of Streptococcus pneumoniae (OXC141 strain) and the strategy used to express, purify and crystallize the recombinant enzyme are described. Diffracting crystals were grown in high-molecular-weight PEG precipitants using the hanging-drop vapour-diffusion method. The best crystal, from which data were collected, diffracted to beyond 2.0 A resolution. Initially, the crystals were thought to belong to space group P4(2)2(1)2, with unit-cell parameters a = 105.5, b = 105.5, c = 62.4 A. However, the R factors remained high following initial processing of the data. It was subsequently shown that the data set was twinned and it was thus reprocessed in space group P2, resulting in a significant reduction in the R factors. Determination of the structure will provide insight into the design of novel antimicrobial agents targeting this important enzyme from S. pneumoniae.
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Affiliation(s)
- Natalia E Sibarani
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
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36
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Voss JE, Scally SW, Taylor NL, Atkinson SC, Griffin MDW, Hutton CA, Parker MW, Alderton MR, Gerrard JA, Dobson RCJ, Dogovski C, Perugini MA. Substrate-mediated stabilization of a tetrameric drug target reveals Achilles heel in anthrax. J Biol Chem 2009; 285:5188-95. [PMID: 19948665 DOI: 10.1074/jbc.m109.038166] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacillus anthracis is a gram-positive spore-forming bacterium that causes anthrax. With the increased threat of anthrax in biowarfare, there is an urgent need to characterize new antimicrobial targets from B. anthracis. One such target is dihydrodipicolinate synthase (DHDPS), which catalyzes the committed step in the pathway yielding meso-diaminopimelate and lysine. In this study, we employed CD spectroscopy to demonstrate that the thermostability of DHDPS from B. anthracis (Ba-DHDPS) is significantly enhanced in the presence of the substrate, pyruvate. Analytical ultracentrifugation studies show that the tetramer-dimer dissociation constant of the enzyme is 3-fold tighter in the presence of pyruvate compared with the apo form. To examine the significance of this substrate-mediated stabilization phenomenon, a dimeric mutant of Ba-DHDPS (L170E/G191E) was generated and shown to have markedly reduced activity compared with the wild-type tetramer. This demonstrates that the substrate, pyruvate, stabilizes the active form of the enzyme. We next determined the high resolution (2.15 A) crystal structure of Ba-DHDPS in complex with pyruvate (3HIJ) and compared this to the apo structure (1XL9). Structural analyses show that there is a significant (91 A(2)) increase in buried surface area at the tetramerization interface of the pyruvate-bound structure. This study describes a new mechanism for stabilization of the active oligomeric form of an antibiotic target from B. anthracis and reveals an "Achilles heel" that can be exploited in structure-based drug design.
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Affiliation(s)
- Jarrod E Voss
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
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37
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Characterisation of dihydrodipicolinate synthase (DHDPS) from Bacillus anthracis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:1510-6. [DOI: 10.1016/j.bbapap.2009.06.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 06/05/2009] [Accepted: 06/25/2009] [Indexed: 11/20/2022]
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Atkinson SC, Dobson RCJ, Newman JM, Gorman MA, Dogovski C, Parker MW, Perugini MA. Crystallization and preliminary X-ray analysis of dihydrodipicolinate synthase from Clostridium botulinum in the presence of its substrate pyruvate. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:253-5. [PMID: 19255476 PMCID: PMC2650466 DOI: 10.1107/s1744309108039018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 11/20/2008] [Indexed: 11/10/2022]
Abstract
In this paper, the crystallization and preliminary X-ray diffraction analysis to near-atomic resolution of DHDPS from Clostridium botulinum crystallized in the presence of its substrate pyruvate are presented. The enzyme crystallized in a number of forms using a variety of PEG precipitants, with the best crystal diffracting to 1.2 A resolution and belonging to space group C2, in contrast to the unbound form, which had trigonal symmetry. The unit-cell parameters were a = 143.4, b = 54.8, c = 94.3 A, beta = 126.3 degrees . The crystal volume per protein weight (V(M)) was 2.3 A(3) Da(-1) (based on the presence of two monomers in the asymmetric unit), with an estimated solvent content of 46%. The high-resolution structure of the pyruvate-bound form of C. botulinum DHDPS will provide insight into the function and stability of this essential bacterial enzyme.
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Affiliation(s)
- Sarah C. Atkinson
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Renwick C. J. Dobson
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Janet M. Newman
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Michael A. Gorman
- St Vincents Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Con Dogovski
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Michael W. Parker
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, Parkville, Victoria 3010, Australia
- St Vincents Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Matthew A. Perugini
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, 30 Flemington Road, Parkville, Victoria 3010, Australia
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Voss JE, Scally SW, Taylor NL, Dogovski C, Alderton MR, Hutton CA, Gerrard JA, Parker MW, Dobson RCJ, Perugini MA. Expression, purification, crystallization and preliminary X-ray diffraction analysis of dihydrodipicolinate synthase from Bacillus anthracis in the presence of pyruvate. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:188-91. [PMID: 19194017 PMCID: PMC2635873 DOI: 10.1107/s1744309109000670] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Accepted: 01/07/2009] [Indexed: 11/11/2022]
Abstract
Dihydrodipicolinate synthase (DHDPS) catalyses the first committed step in the lysine-biosynthesis pathway in bacteria, plants and some fungi. In this study, the expression of DHDPS from Bacillus anthracis (Ba-DHDPS) and the purification of the recombinant enzyme in the absence and presence of the substrate pyruvate are described. It is shown that DHDPS from B. anthracis purified in the presence of pyruvate yields greater amounts of recombinant enzyme with more than 20-fold greater specific activity compared with the enzyme purified in the absence of substrate. It was therefore sought to crystallize Ba-DHDPS in the presence of the substrate. Pyruvate was soaked into crystals of Ba-DHDPS prepared in 0.2 M sodium fluoride, 20%(w/v) PEG 3350 and 0.1 M bis-tris propane pH 8.0. Preliminary X-ray diffraction data of the recombinant enzyme soaked with pyruvate at a resolution of 2.15 A are presented. The pending crystal structure of the pyruvate-bound form of Ba-DHDPS will provide insight into the function and stability of this essential bacterial enzyme.
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Affiliation(s)
- Jarrod E Voss
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
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