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Mirabal B, Andrade BS, Souza SPA, Oliveira IBDS, Melo TS, Barbosa FS, Jaiswal AK, Seyffert N, Portela RW, Soares SDC, Azevedo V, Meyer R, Tiwari S, Castro TLDP. In silico approaches for predicting natural compounds with therapeutic potential and vaccine candidates against Streptococcus equi. J Biomol Struct Dyn 2024:1-15. [PMID: 38239063 DOI: 10.1080/07391102.2023.2301056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 12/26/2023] [Indexed: 01/26/2024]
Abstract
Equine strangles is a prevalent disease that affects the upper respiratory in horses and is caused by the Gram-positive bacterium Streptococcus equi. In addition to strangles, other clinical conditions are caused by the two S. equi subspecies, equi and zooepidemicus, which present relevant zoonotic potential. Treatment of infections caused by S. equi has become challenging due to the worldwide spreading of infected horses and the unavailability of effective therapeutics and vaccines. Penicillin treatment is often recommended, but multidrug resistance issues arised. We explored the whole genome sequence of 18 S. equi isolates to identify candidate proteins to be targeted by natural drug-like compounds or explored as immunogens. We considered only proteins shared among the sequenced strains of subspecies equi and zooepidemicus, absent in the equine host and predicted to be essential and involved in virulence. Of these, 4 proteins with cytoplasmic subcellular location were selected for molecular docking with a library of 5008 compounds, while 6 proteins were proposed as prominent immunogens against S. equi due to their probabilities of behaving as adhesins. The molecular docking analyses revealed the best ten ligands for each of the 4 drug target candidates, and they were ranked according to their binding affinities and the number of hydrogen bonds for complex stability. Finally, the natural 5-ring compound C25H20F3N5O3 excelled in molecular dynamics simulations for the increased stability in the interaction with UDP-N-acetylenolpyruvoylglucosamine reductase (MurB). This research paves the way to developing new therapeutics to minimize the impacts caused by S. equi infections.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Bernardo Mirabal
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Bruno Silva Andrade
- Department of Biological Sciences, State University of Southwest Bahia, Jequié, Brazil
| | | | | | - Tarcisio Silva Melo
- Postgraduate Program in Biotechnology, State University of Feira de Santana (UEFS), Feira de Santana, Brazil
| | - Fabrício Santos Barbosa
- Postgraduate Program in Chemistry, State University of Southwest Bahia (UESB), Jequié, Brazil
| | - Arun Kumar Jaiswal
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Nubia Seyffert
- Institute of Health Sciences, Federal University of Bahia, Salvador, Brazil
| | | | - Siomar de Castro Soares
- Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro, Uberaba, Brazil
| | - Vasco Azevedo
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
- School of Veterinary Medicine and Animal Science, Federal University of Bahia, Salvador, Brazil
| | - Roberto Meyer
- Institute of Health Sciences, Federal University of Bahia, Salvador, Brazil
| | - Sandeep Tiwari
- Institute of Health Sciences, Federal University of Bahia, Salvador, Brazil
| | - Thiago Luiz de Paula Castro
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
- Institute of Health Sciences, Federal University of Bahia, Salvador, Brazil
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2
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DeMeester KE, Liang H, Zhou J, Wodzanowski KA, Prather BL, Santiago CC, Grimes CL. Metabolic Incorporation of N-Acetyl Muramic Acid Probes into Bacterial Peptidoglycan. ACTA ACUST UNITED AC 2020; 11:e74. [PMID: 31763799 DOI: 10.1002/cpch.74] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial cells utilize small carbohydrate building blocks to construct peptidoglycan (PG), a highly conserved mesh-like polymer that serves as a protective coat for the cell. PG production has long been a target for antibiotics, and its breakdown is a source for human immune recognition. A key component of bacterial PG, N-acetyl muramic acid (NAM), is a vital element in many synthetically derived immunostimulatory compounds. However, the exact molecular details of these structures and how they are generated remain unknown due to a lack of chemical probes surrounding the NAM core. A robust synthetic strategy to generate bioorthogonally tagged NAM carbohydrate units is implemented. These molecules serve as precursors for PG biosynthesis and recycling. Escherichia coli cells are metabolically engineered to incorporate the bioorthogonal NAM probes into their PG network. The probes are subsequently modified using copper-catalyzed azide-alkyne cycloaddition to install fluorophores directly into the bacterial PG, as confirmed by super-resolution microscopy and high-resolution mass spectrometry. Here, synthetic notes for key elements of this process to generate the sugar probes as well as streamlined user-friendly metabolic labeling strategies for both microbiology and immunological applications are described. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1: Synthesis of peracetylated 2-azido glucosamine Basic Protocol 2: Synthesis of 2-azido and 2-alkyne NAM Basic Protocol 3: Synthesis of 3-azido NAM methyl ester Basic Protocol 4: Incorporation of NAM probes into bacterial peptidoglycan Basic Protocol 5: Confirmation of bacterial cell wall remodeling by mass spectrometry.
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Affiliation(s)
- Kristen E DeMeester
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware
| | - Hai Liang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware.,Cutaneous Microbiome and Inflammation Section, Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, Maryland
| | - Junhui Zhou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware
| | | | - Benjamin L Prather
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware
| | - Cintia C Santiago
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware.,Center for the Study of Organic Compounds, CEDECOR-UNLP-CIC, Department of Chemistry, Faculty of Exact Sciences, National University of La Plata, Buenos Aires, Argentina
| | - Catherine L Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware.,Department of Biological Sciences, University of Delaware, Newark, Delaware
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3
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Mehla K, Ramana J. Tapping into Salmonella typhimurium LT2 genome in a quest to explore its therapeutic arsenal: A metabolic network modeling approach. Biomed Pharmacother 2016; 86:57-66. [PMID: 27939520 DOI: 10.1016/j.biopha.2016.11.129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 11/24/2016] [Accepted: 11/27/2016] [Indexed: 01/17/2023] Open
Abstract
S. typhimurium, the classical broad-host-range serovar is a widely distributed cause of food-borne illness. Escalating antibiotic resistance and potential of conjugal transmission to other pathogens attributable to its broad spectrum host specificities have aided S. typhimurium to emerge as a global health threat. To keep pace with ever evolving bacterial defenses, there is dire need to restock the antibiotic pipeline. Genome scale metabolic reconstructions present immense possibilities to decipher physiological properties of an organism using constraint-based methods The systems-level approaches of genome scale metabolic networks interrogation open up new avenues of drug target identification against deadly infectious diseases. We performed flux balance analysis and minimization of metabolic adjustment studies of genome scale reconstruction model of S. typhimurium targeted at identifying large number of metabolites with a potential to be utilized as therapeutic drug targets. These constraint based approaches initially predict a set of genes indispensable to bacterial survival by performing gene knockout studies which are then prioritized through a multistep process. Metabolites involved in l-rhamnose biosynthesis, peptidoglycan biosynthesis, fatty acid biosynthesis, and folate biosynthesis pathways were prioritized as candidate drug targets. This study provides a general therapeutic approach which can be effectively applied to other pathogens as well.
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Affiliation(s)
- Kusum Mehla
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, PIN 173234 Himachal Pradesh, India
| | - Jayashree Ramana
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, PIN 173234 Himachal Pradesh, India.
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Naqvi KF, Patin D, Wheatley MS, Savka MA, Dobson RCJ, Gan HM, Barreteau H, Blanot D, Mengin-Lecreulx D, Hudson AO. Identification and Partial Characterization of a Novel UDP-N-Acetylenolpyruvoylglucosamine Reductase/UDP-N-Acetylmuramate:l-Alanine Ligase Fusion Enzyme from Verrucomicrobium spinosum DSM 4136(T). Front Microbiol 2016; 7:362. [PMID: 27047475 PMCID: PMC4803751 DOI: 10.3389/fmicb.2016.00362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/07/2016] [Indexed: 11/13/2022] Open
Abstract
The enzymes involved in synthesizing the bacterial cell wall are attractive targets for the design of antibacterial compounds, since this pathway is essential for bacteria and is absent in animals, particularly humans. A survey of the genome of a bacterium that belongs to the phylum Verrucomicrobia, the closest free-living relative to bacteria from the Chlamydiales phylum, shows genetic evidence that Verrucomicrobium spinosum possesses a novel fusion open reading frame (ORF) annotated by the locus tag (VspiD_010100018130). The ORF, which is predicted to encode the enzymes UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and UDP-N-acetylmuramate:l-alanine ligase (MurC) that are involved in the cytoplasmic steps of peptidoglycan biosynthesis, was cloned. In vivo analyses using functional complementation showed that the fusion gene was able to complement Escherichia coli murB and murC temperature sensitive mutants. The purified recombinant fusion enzyme (MurB/CVs) was shown to be endowed with UDP-N-acetylmuramate:l-alanine ligase activity. In vitro analyses demonstrated that the latter enzyme had a pH optimum of 9.0, a magnesium optimum of 10 mM and a temperature optimum of 44–46°C. Its apparent Km values for ATP, UDP-MurNAc, and l-alanine were 470, 90, and 25 μM, respectively. However, all attempts to demonstrate an in vitro UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) activity were unsuccessful. Lastly, Hidden Markov Model-based similarity search and phylogenetic analysis revealed that this fusion enzyme could only be identified in specific lineages within the Verrucomicrobia phylum.
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Affiliation(s)
- Kubra F Naqvi
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester, NY, USA
| | - Delphine Patin
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay Orsay, France
| | - Matthew S Wheatley
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester, NY, USA
| | - Michael A Savka
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester, NY, USA
| | - Renwick C J Dobson
- Biomolecular Interaction Centre, School of Biological Sciences, University of CanterburyChristchurch, New Zealand; Department of Biochemistry and Molecular Biology, Bio21 Molecular and Biotechnology Institute, The University of MelbourneParkville, VIC, Australia
| | - Han Ming Gan
- Monash University Malaysia Genomics Facility, Monash University MalaysiaSelangor, Malaysia; School of Science, Monash University MalaysiaSelangor, Malaysia
| | - Hélène Barreteau
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay Orsay, France
| | - Didier Blanot
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay Orsay, France
| | - Dominique Mengin-Lecreulx
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay Orsay, France
| | - André O Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester, NY, USA
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Mehla K, Ramana J. Novel Drug Targets for Food-Borne Pathogen Campylobacter jejuni: An Integrated Subtractive Genomics and Comparative Metabolic Pathway Study. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2015; 19:393-406. [PMID: 26061459 DOI: 10.1089/omi.2015.0046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Campylobacters are a major global health burden and a cause of food-borne diarrheal illness and economic loss worldwide. In developing countries, Campylobacter infections are frequent in children under age two and may be associated with mortality. In developed countries, they are a common cause of bacterial diarrhea in early adulthood. In the United States, antibiotic resistance against Campylobacter is notably increased from 13% in 1997 to nearly 25% in 2011. Novel drug targets are urgently needed but remain a daunting task to accomplish. We suggest that omics-guided drug discovery is timely and worth considering in this context. The present study employed an integrated subtractive genomics and comparative metabolic pathway analysis approach. We identified 16 unique pathways from Campylobacter when compared against H. sapiens with 326 non-redundant proteins; 115 of these were found to be essential in the Database of Essential Genes. Sixty-six proteins among these were non-homologous to the human proteome. Six membrane proteins, of which four are transporters, have been proposed as potential vaccine candidates. Screening of 66 essential non-homologous proteins against DrugBank resulted in identification of 34 proteins with drug-ability potential, many of which play critical roles in bacterial growth and survival. Out of these, eight proteins had approved drug targets available in DrugBank, the majority serving crucial roles in cell wall synthesis and energy metabolism and therefore having the potential to be utilized as drug targets. We conclude by underscoring that screening against these proteins with inhibitors may aid in future discovery of novel therapeutics against campylobacteriosis in ways that will be pathogen specific, and thus have minimal toxic effect on host. Omics-guided drug discovery and bioinformatics analyses offer the broad potential for veritable advances in global health relevant novel therapeutics.
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Affiliation(s)
- Kusum Mehla
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology , Solan, Himachal Pradesh, India
| | - Jayashree Ramana
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology , Solan, Himachal Pradesh, India
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6
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Gautam A, Vyas R, Tewari R. Peptidoglycan biosynthesis machinery: a rich source of drug targets. Crit Rev Biotechnol 2010; 31:295-336. [PMID: 21091161 DOI: 10.3109/07388551.2010.525498] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The range of antibiotic therapy for the control of bacterial infections is becoming increasingly limited because of the rapid rise in multidrug resistance in clinical bacterial isolates. A few diseases, such as tuberculosis, which were once thought to be under control, have re-emerged as serious health threats. These problems have resulted in intensified research to look for new inhibitors for bacterial pathogens. Of late, the peptidoglycan (PG) layer, the most important component of the bacterial cell wall has been the subject of drug targeting because, first, it is essential for the survivability of eubacteria and secondly, it is absent in humans. The last decade has seen tremendous inputs in deciphering the 3-D structures of the PG biosynthetic enzymes. Many inhibitors against these enzymes have been developed using virtual and high throughput screening techniques. This review discusses the mechanistic and structural properties of the PG biosynthetic enzymes and inhibitors developed in the last decade.
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Affiliation(s)
- Ankur Gautam
- Department of Biotechnology, Panjab University, Chandigarh, India
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7
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van Dam V, Olrichs N, Breukink E. Specific labeling of peptidoglycan precursors as a tool for bacterial cell wall studies. Chembiochem 2009; 10:617-24. [PMID: 19173317 DOI: 10.1002/cbic.200800678] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Because of its importance for bacterial cell survival, the bacterial cell wall is an attractive target for new antibiotics in a time of great demand for new antibiotic compounds. Therefore, more knowledge about the diverse processes related to bacterial cell wall synthesis is needed. The cell wall is located on the exterior of the cell and consists mainly of peptidoglycan, a large macromolecule built up from a three-dimensional network of aminosugar strands interlinked with peptide bridges. The subunits of peptidoglycan are synthesized inside the cell before they are transported to the exterior in order to be incorporated into the growing peptidoglycan. The high flexibility of the cell wall synthesis machinery towards unnatural derivatives of these subunits enables research on the bacterial cell wall using labeled compounds. This review highlights the high potential of labeled cell wall precursors in various areas of cell wall research. Labeled precursors can be used in investigating direct cell wall-antibiotic interactions and in cell wall synthesis and localization studies. Moreover, these compounds can provide a powerful tool in the elucidation of the cell wall proteome, the "wallosome," and thus, might provide new targets for antibiotics.
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Affiliation(s)
- Vincent van Dam
- Chemical Biology and Organic Chemistry, Bijvoet Center for Biomolecular Research and Institute of Biomembranes, Utrecht University, Padualaan 8, Utrecht, The Netherlands
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8
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Lery LMS, Coelho A, von Kruger WMA, Gonçalves MSM, Santos MF, Valente RH, Santos EO, Rocha SLG, Perales J, Domont GB, Teixeira KRS, Bertalan M, Ferreira PCG, Bisch PM. Protein expression profile of Gluconacetobacter diazotrophicus PAL5, a sugarcane endophytic plant growth-promoting bacterium. Proteomics 2008; 8:1631-44. [PMID: 18340630 DOI: 10.1002/pmic.200700912] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This is the first broad proteomic description of Gluconacetobacter diazotrophicus, an endophytic bacterium, responsible for the major fraction of the atmospheric nitrogen fixed in sugarcane in tropical regions. Proteomic coverage of G. diazotrophicus PAL5 was obtained by two independent approaches: 2-DE followed by MALDI-TOF or TOF-TOF MS and 1-DE followed by chromatography in a C18 column online coupled to an ESI-Q-TOF or ESI-IT mass spectrometer. The 583 identified proteins were sorted into functional categories and used to describe potential metabolic pathways for nucleotides, amino acids, carbohydrates, lipids, cofactors and energy production, according to the Enzyme Commission of Enzyme Nomenclature (EC) and Kyoto Encyclopedia of genes and genomes (KEGG) databases. The identification of such proteins and their possible insertion in conserved biochemical routes will allow comparisons between G. diazotrophicus and other bacterial species. Furthermore, the 88 proteins classified as conserved unknown or unknown constitute a potential target for functional genomic studies, aiming at the understanding of protein function and regulation of gene expression. The knowledge of metabolic fundamentals and coordination of these actions are crucial for the rational, safe and sustainable interference on crops. The entire dataset, including peptide sequence information, is available as Supporting Information and is the major contribution of this work.
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Kedar GC, Brown-Driver V, Reyes DR, Hilgers MT, Stidham MA, Shaw KJ, Finn J, Haselbeck RJ. Evaluation of the metS and murB loci for antibiotic discovery using targeted antisense RNA expression analysis in Bacillus anthracis. Antimicrob Agents Chemother 2007; 51:1708-18. [PMID: 17339372 PMCID: PMC1855544 DOI: 10.1128/aac.01180-06] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The biowarfare-relevant bacterial pathogen Bacillus anthracis contains two paralogs each of the metS and murB genes, which encode the important antibiotic target functions methionyl-tRNA synthetase and UDP-N-acetylenolpyruvoylglucosamine reductase, respectively. Empirical screens were conducted to detect and characterize gene fragments of each of these four genes that could cause growth reduction of B. anthracis when inducibly expressed from a plasmid-borne promoter. Numerous such gene fragments that were overwhelmingly in the antisense orientation were identified for the metS1 and murB2 alleles, while no such orientation bias was seen for the metS2 and murB1 alleles. Gene replacement mutagenesis was used to confirm the essentiality of the metS1 and murB2 alleles, and the nonessentiality of the metS2 and murB1 alleles, for vegetative growth. Induced transcription of RNA from metS1 and murB2 antisense-oriented gene fragments resulted in specific reduction of mRNA of their cognate genes. Attenuation of MetS1 enzyme expression hypersensitized B. anthracis cells to a MetS-specific antimicrobial compound but not to other antibiotics that affect cell wall assembly, fatty acid biosynthesis, protein translation, or DNA replication. Antisense-dependent reduction of MurB2 enzyme expression caused hypersensitivity to beta-lactam antibiotics, a synergistic response that has also been noted for the MurA-specific antibiotic fosfomycin. These experiments form the basis of mode-of-action detection assays that can be used in the discovery of novel MetS- or MurB-specific antibiotic drugs that are effective against B. anthracis or other gram-positive bacterial pathogens.
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Affiliation(s)
- G C Kedar
- Trius Therapeutics Inc, San Diego, CA 92121, USA
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10
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Real G, Henriques AO. Localization of the Bacillus subtilis murB gene within the dcw cluster is important for growth and sporulation. J Bacteriol 2006; 188:1721-32. [PMID: 16484183 PMCID: PMC1426548 DOI: 10.1128/jb.188.5.1721-1732.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Bacillus subtilis murB gene, encoding UDP-N-acetylenolpyruvoylglucosamine reductase, a key enzyme in the peptidoglycan (PG) biosynthetic pathway, is embedded in the dcw (for "division and cell wall") cluster immediately upstream of divIB. Previous attempts to inactivate murB were unsuccessful, suggesting its essentiality. Here we show that the cell morphology, growth rate, and resistance to cell wall-active antibiotics of murB conditional mutants is a function of the expression level of murB. In one mutant, in which murB was insertionally inactivated in a merodiploid bearing a second xylose-inducible PxylA-murB allele, DivIB levels were reduced and a normal growth rate was achieved only if MurB levels were threefold that of the wild-type strain. However, expression of an extra copy of divIB restored normal growth at wild-type levels of MurB. In contrast, DivIB levels were normal in a second mutant containing an in-frame deletion of murB (DeltamurB) in the presence of the PxylA-murB gene. Furthermore, this strain grew normally with wild-type levels of MurB. During sporulation, the levels of MurB were highest at the time of synthesis of the spore cortex PG. Interestingly, the DeltamurB PxylA-murB mutant did not sporulate efficiently even at high concentrations of inducer. Since high levels of inducer did not interfere with sporulation of a murB(+)PxylA-murB strain, it appears that ectopic expression of murB fails to support efficient sporulation. These data suggest that coordinate expression of divIB and murB is important for growth and sporulation. The genetic context of the murB gene within the dcw cluster is unique to the Bacillus group and, taken together with our data, suggests that in these species it contributes to the optimal expression of cell division and PG biosynthetic functions during both vegetative growth and spore development.
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Affiliation(s)
- Gonçalo Real
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901 Oeiras Codex, Portugal.
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Raymond JB, Price NP, Pavelka MS. A method for the enzymatic synthesis and HPLC purification of the peptidoglycan precursor UDP-N-acetylmuramic acid. FEMS Microbiol Lett 2004; 229:83-9. [PMID: 14659546 DOI: 10.1016/s0378-1097(03)00793-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
UDP-N-acetylmuramic acid (UDP-MurNAc) is a precursor for peptidoglycan biosynthesis in bacteria. A major difficulty in the study of this pathway is that UDP-MurNAc is not commercially available. We have developed an enzymatic synthesis scheme for UDP-MurNAc using two easily purified Escherichia coli polyhistidine tagged peptidoglycan biosynthesis enzymes, MurZ and MurB, followed by a single-step purification of UDP-MurNAc by high-performance liquid chromatography. The identity of the UDP-MurNAc synthesized by our method was confirmed by electrospray ionization mass spectrometry. Furthermore, we show that the UDP-MurNAc can support a UDP-MurNAc-L-alanine ligase reaction.
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Affiliation(s)
- Jon B Raymond
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box 672, Rochester, NY 14642, USA
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Matsuo M, Kurokawa K, Nishida S, Li Y, Takimura H, Kaito C, Fukuhara N, Maki H, Miura K, Murakami K, Sekimizu K. Isolation and mutation site determination of the temperature-sensitive murB mutants of Staphylococcus aureus. FEMS Microbiol Lett 2003; 222:107-13. [PMID: 12757953 DOI: 10.1016/s0378-1097(03)00260-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The murB gene encodes UDP-N-acetylenolpyruvylglucosamine reductase and functions in bacterial peptidoglycan biosynthesis. A plasmid carrying the murB gene restored the temperature-sensitive growth of six Staphylococcus aureus mutants, in which peptidoglycan biosynthesis stopped at a restrictive temperature. Specific activity of UDP-N-acetylenolpyruvylglucosamine reductase in extracts from the mutants was lower than that from wild-type cells. Nucleotide sequence determination revealed that each mutant had a single amino acid substitution in the murB gene and five of six mutations were located within domain 3, where the proposed substrate binding site is located. These results suggest that the murB gene is essential for growth of S. aureus and that domain 3 is important for the MurB activity.
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Affiliation(s)
- Miki Matsuo
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 3-1, 7-Chome, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Bronson JJ, DenBleyker KL, Falk PJ, Mate RA, Ho HT, Pucci MJ, Snyder LB. Discovery of the first antibacterial small molecule inhibitors of MurB. Bioorg Med Chem Lett 2003; 13:873-5. [PMID: 12617911 DOI: 10.1016/s0960-894x(02)01076-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A series of imidazolinone analogues was synthesized and shown to possess potent MurB inhibitory as well as good antibacterial activity.
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Affiliation(s)
- Joanne J Bronson
- Bristol-Myers Squibb Pharmaceutical Research Institute, 5 Research Parkway, Wallingford, CT 06492, USA
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Bouhss A, Dementin S, van Heijenoort J, Parquet C, Blanot D. MurC and MurD synthetases of peptidoglycan biosynthesis: borohydride trapping of acyl-phosphate intermediates. Methods Enzymol 2003; 354:189-96. [PMID: 12418226 DOI: 10.1016/s0076-6879(02)54015-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ahmed Bouhss
- UMR 8619 CNRS, Université de Paris-Sud, 91405 Orsay, France
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15
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Sylvester DR, Alvarez E, Patel A, Ratnam K, Kallender H, Wallis NG. Identification and characterization of UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from the Gram-positive pathogen Streptococcus pneumoniae. Biochem J 2001; 355:431-5. [PMID: 11284731 PMCID: PMC1221755 DOI: 10.1042/0264-6021:3550431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from a Gram-positive pathogen, Streptococcus pneumoniae, was identified and characterized. The enzyme from S. pneumoniae shows 31% identity with the MurB protein from Escherichia coli, and contains the catalytic residues, substrate-binding residues and FAD-binding motif identified previously in the E. coli protein. The gene was cloned into the pET28a+ expression vector, and the 34.5 kDa protein that it encodes was overexpressed in E. coli strain BL21(DE3) to 30% of total cell protein. The majority of the protein was found to be insoluble. A variety of methods were used to increase the amount of soluble protein to 10%. This was then purified to near homogeneity in a two-step process. The absorption spectrum of the purified protein indicated it to be a flavoprotein, like its E. coli homologue, with a characteristic absorption at 463 nm. The enzyme was shown to be active, reducing UDP-N-acetylglucosamine enolpyruvate with the concomitant oxidation of NADPH, and was characterized kinetically with respect to its two substrates. The enzyme showed properties similar to those of its E. coli counterpart, being activated by univalent cations and being subject to substrate inhibition. The characterization of an important cell wall biosynthesis enzyme from a Gram-positive pathogen provides a good starting point for the discovery of antibacterial agents against MurB.
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Affiliation(s)
- D R Sylvester
- Department of Anti-Infective Research, SmithKline Beecham Pharmaceuticals, 1250 South Collegeville Road, Collegeville, PA 19426, USA
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16
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Hare RS, Walker SS, Dorman TE, Greene JR, Guzman LM, Kenney TJ, Sulavik MC, Baradaran K, Houseweart C, Yu H, Foldes Z, Motzer A, Walbridge M, Shimer GH, Shaw KJ. Genetic footprinting in bacteria. J Bacteriol 2001; 183:1694-706. [PMID: 11160101 PMCID: PMC95055 DOI: 10.1128/jb.183.5.1694-1706.2001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In vivo genetic footprinting was developed in the yeast Saccharomyces cerevisiae to simultaneously assess the importance of thousands of genes for the fitness of the cell under any growth condition. We have developed in vivo genetic footprinting for Escherichia coli, a model bacterium and pathogen. We further demonstrate the utility of this technology for rapidly discovering genes that affect the fitness of E. coli under a variety of growth conditions. The definitive features of this system include a conditionally regulated Tn10 transposase with relaxed sequence specificity and a conditionally regulated replicon for the vector containing the transposase and mini-Tn10 transposon with an outwardly oriented promoter. This system results in a high frequency of randomly distributed transposon insertions, eliminating the need for the selection of a population containing transposon insertions, stringent suppression of transposon mutagenesis, and few polar effects. Successful footprints have been achieved for most genes longer than 400 bp, including genes located in operons. In addition, the ability of recombinant proteins to complement mutagenized hosts has been evaluated by genetic footprinting using a bacteriophage lambda transposon delivery system.
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Affiliation(s)
- R S Hare
- Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
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17
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Benson TE, Harris MS, Choi GH, Cialdella JI, Herberg JT, Martin JP, Baldwin ET. A structural variation for MurB: X-ray crystal structure of Staphylococcus aureus UDP-N-acetylenolpyruvylglucosamine reductase (MurB). Biochemistry 2001; 40:2340-50. [PMID: 11327854 DOI: 10.1021/bi002162d] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The X-ray crystal structure of the substrate free form of Staphylococcus aureus UDP-N-acetylenolpyruvylglucosamine reductase (MurB) has been solved to 2.3 A resolution with an R-factor of 20.3% and a free R-factor of 22.3%. While the overall fold of the S. aureus enzyme is similar to that of the homologous Escherichia coli MurB X-ray crystal structure, notable distinctions between the S. aureus and E. coli MurB protein structures occur in residues involved in substrate binding. Analysis of available MurB sequences from other bacteria suggest that the S. aureus MurB structure is representative of a distinct structural class of UDP-N-acetylenolpyruvylglucosamine reductases including Bacillus subtilis and Helicobacter pylori that are characterized by a modified mechanism for substrate binding.
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Affiliation(s)
- T E Benson
- Structural, Analytical, and Medicinal Chemistry, Biology, and Protein Science, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49007, USA.
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18
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Abstract
This map is an update of the edition 9 map by Berlyn et al. (M. K. B. Berlyn, K. B. Low, and K. E. Rudd, p. 1715-1902, in F. C. Neidhardt et al., ed., Escherichia coli and Salmonella: cellular and molecular biology, 2nd ed., vol. 2, 1996). It uses coordinates established by the completed sequence, expressed as 100 minutes for the entire circular map, and adds new genes discovered and established since 1996 and eliminates those shown to correspond to other known genes. The latter are included as synonyms. An alphabetical list of genes showing map location, synonyms, the protein or RNA product of the gene, phenotypes of mutants, and reference citations is provided. In addition to genes known to correspond to gene sequences, other genes, often older, that are described by phenotype and older mapping techniques and that have not been correlated with sequences are included.
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Affiliation(s)
- M K Berlyn
- Department of Biology and School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06520-8104, USA.
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19
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Pucci MJ, Thanassi JA, Discotto LF, Kessler RE, Dougherty TJ. Identification and characterization of cell wall-cell division gene clusters in pathogenic gram-positive cocci. J Bacteriol 1997; 179:5632-5. [PMID: 9287029 PMCID: PMC179445 DOI: 10.1128/jb.179.17.5632-5635.1997] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Clusters of peptidoglycan biosynthesis and cell division genes (DCW genes) were identified and sequenced in two gram-positive cocci, Staphylococcus aureus and Enterococcus faecalis. The results indicated some similarities in organization compared with previously reported bacterial DCW gene clusters, including the presence of penicillin-binding proteins at the left ends and ftsA and ftsZ cell division genes at the right ends of the clusters. However, there were also some important differences, including the absence of several genes, the comparative sizes of the div1B and ftsQ genes, and a wide range of amino acid sequence similarities when the genes of the gram-positive cocci were translated and compared to bacterial homologs.
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Affiliation(s)
- M J Pucci
- Department of Microbiology, Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, Connecticut 06492, USA.
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20
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Constantine KL, Mueller L, Goldfarb V, Wittekind M, Metzler WJ, Yanchunas J, Robertson JG, Malley MF, Friedrichs MS, Farmer BT. Characterization of NADP+ binding to perdeuterated MurB: backbone atom NMR assignments and chemical-shift changes. J Mol Biol 1997; 267:1223-46. [PMID: 9150408 DOI: 10.1006/jmbi.1997.0915] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Backbone-atom resonances have been assigned for both the substrate-free and the NADP+-complexed forms of UDP-N-acetylenolpyruvylglucosamine reductase (MurB), a monomeric, 347-residue (38.5 kDa) flavoenzyme essential for bacterial cell-wall biosynthesis. NMR studies were performed using perdeuterated, uniformly 13C/15N-labeled samples of MurB. In the case of substrate-free MurB, one or more backbone atoms have been assigned for 334 residues (96%). The assigned backbone atoms include 309 1HN and 15N atoms (94%), 315 13CO atoms (91%), 331 13C(alpha) atoms (95%), and 297 13C(beta) atoms (93%). For NADP+-complexed MurB, one or more backbone atoms have been assigned for 313 residues (90%); these include 283 1HN and 15N atoms (86%), 305 13CO atoms (88%), 310 13C(alpha) atoms (89%), and 269 13C(beta) atoms (84%). The strategies used for obtaining resonance assignments are described in detail. Information on the secondary structure in solution for both the substrate-free and NADP+-complexed forms of the enzyme has been derived both from 13C(alpha) and 13C(beta) chemical-shift deviations from random-coil values and from 1HN-1HN NOEs. These data are compared to X-ray crystallographic structures of substrate-free MurB and MurB complexed with the UDP-N-acetylglucosamine enolpyruvate (UNAGEP) substrate. NADP+ binding induces significant chemical-shift changes in residues both within the known UNAGEP and FAD binding pockets and within regions known to undergo conformational changes upon UNAGEP binding. The NMR data indicate that NADP+ and UNAGEP utilize the same binding pocket and, furthermore, that the binding of NADP+ induces structural changes in MurB. Finally, many of the residues within the UNAGEP/NADP+ binding pocket were difficult to assign due to dynamic processes which weaken and/or broaden the respective resonances. Overall, our results are consistent with MurB having a flexible active site.
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Affiliation(s)
- K L Constantine
- Division of Macromolecular Structure, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543-4000, USA
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21
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Axley MJ, Fairman R, Yanchunas J, Villafranca JJ, Robertson JG. Spectroscopic properties of Escherichia coli UDP-N-acetylenolpyruvylglucosamine reductase. Biochemistry 1997; 36:812-22. [PMID: 9020779 DOI: 10.1021/bi962260s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purified uridine diphosphate N-acetylenolpyruvylglucosamine reductase (E.C. 1.1.1.158) was analyzed by circular dichroism (CD) and UV-visible spectroscopy to establish the spectral properties of its tightly bound flavin adenine dinucleotide (FAD) cofactor. The polypeptide backbone displayed a single circular dichroic minimum at 208 nm and a single maximum at 193 nm. The CD spectrum of bound flavin exhibited a single major negative Cotton peak at 364 nm and two minor negative Cotton peaks at 464 and 495 nm. The protein was reversibly unfolded in 9.8 M urea and refolded in buffer in the presence of excess FAD. The refolded enzyme incorporated FAD and catalyzed full activity. The bound FAD displayed an absorption maximum at 464 nm with an extinction coefficient of epsilon 464 = 11700 M-1 cm-1. Anaerobic reduction with dithionite was complete at 1 equiv. Anaerobic reduction with nicotinamide adenine dinucleotide phosphate, reduced form (NADPH), also was essentially complete at 1 equiv and produced a long-wavelength absorbance band characteristic of an FAD-pyridine nucleotide charge transfer complex. Photochemical bleaching in the presence of ethylenediaminetetraacetic acid (EDTA) followed exponential kinetics. None of the anaerobic reductive titrations produced a spectral intermediate characteristic of a flavin semiquinone, and all reduced enzyme species could be fully reoxidized by oxygen, with full recovery of catalytic activity. Photochemically reduced enzyme was reoxidized by titration with either NADP+ or uridine diphospho N-acetylglucosamine enolpyruvate (UNAGEP). Reoxidation by NADP+ reached a chemical equilibrium, whereas reoxidation by UNAGEP was stoichiometric. Binding of NADP+ or UNAGEP to the oxidized form of the enzyme produced a dead-end complex that could be titrated by following a 10-nm red shift in the absorption spectrum of the bound FAD. The Kd of NADP+ for oxidized enzyme was 0.7 +/- 0.3 microM and the Kd of UNAGEP was 2.7 +/- 0.3 microM. Solvent deuterium isotope effects on binding were observed for both NADP+ and UNAGEP, depending on the pH. At pH 8.5, the HKd/DKd was 2.2 for NADP+ and 3.9 for UNAGEP. No spectral changes were observed in the presence of a 40-fold excess of uridine diphospho N-acetylmuramic acid (UNAM) either aerobically or anaerobically. These studies have identified spectral signals for five steps in the kinetic mechanism, have indicated that product formation is essentially irreversible, and have indicated that hydrogen bonding or protonation contributes significantly to ground-state complex formation with the physiological substrate.
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Affiliation(s)
- M J Axley
- Enzymology Laboratory, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543-4000, USA
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22
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Farmer BT, Constantine KL, Goldfarb V, Friedrichs MS, Wittekind M, Yanchunas J, Robertson JG, Mueller L. Localizing the NADP+ binding site on the MurB enzyme by NMR. NATURE STRUCTURAL BIOLOGY 1996; 3:995-7. [PMID: 8946851 DOI: 10.1038/nsb1296-995] [Citation(s) in RCA: 184] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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23
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Rowland SL, Errington J, Wake RG. The Bacillus subtilis cell-division 135-137 degrees region contains an essential orf with significant similarity to murB and a dispensable sbp gene. Gene 1995; 164:113-6. [PMID: 7590298 DOI: 10.1016/0378-1119(95)00467-k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sequence similarity analysis has revealed that orf2, in the cell division 135-137 degrees region of the Bacillus subtilis (Bs) chromosome, is the probable homolog of Escherichia coli murB (encoding a reductase involved in peptidoglycan synthesis). The amino-acid sequences of the two protein products show 24% identity (47% overall similarity), with several regions of higher similarity which may represent functional domains of the proteins. Attempts to insertionally inactivate orf2 were unsuccessful, strongly suggesting that it is an essential Bs gene. A small gene found in the same region as orf2, sbp (encoding the 'small basic protein'), was shown to be non-essential in Bs.
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Affiliation(s)
- S L Rowland
- Department of Biochemistry, University of Sydney, NSW, Australia
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24
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Benson TE, Filman DJ, Walsh CT, Hogle JM. An enzyme-substrate complex involved in bacterial cell wall biosynthesis. NATURE STRUCTURAL BIOLOGY 1995; 2:644-53. [PMID: 7552726 DOI: 10.1038/nsb0895-644] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The crystal structure of UDP-N-acetylenolpyruvylglucosamine reductase in the presence of its substrate, enolpyruvyl-UDP-N-acetylglucosamine, has been solved to 2.7 A resolution. This enzyme is responsible for the synthesis of UDP-N-acetylmuramic acid in bacterial cell wall biosynthesis and consequently provides an attractive target for the design of antibacterial agents. The structure reveals a novel flavin binding motif, shows a striking alignment of the flavin with the substrate, and suggests a catalytic mechanism for the reduction of this unusual enol ether.
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Affiliation(s)
- T E Benson
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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25
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Benson TE, Walsh CT, Hogle JM. Crystallization and preliminary X-ray crystallographic studies of UDP-N-acetylenolpyruvylglucosamine reductase. Protein Sci 1994; 3:1125-7. [PMID: 7920261 PMCID: PMC2142893 DOI: 10.1002/pro.5560030718] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The overexpression and purification of the second enzyme in Escherichia coli peptidoglycan biosynthesis, UDP-N-acetylenolpyruvylglucosamine reductase (MurB), provided sufficient protein to undertake crystallization and X-ray crystallographic studies of the enzyme. MurB crystallizes in 14-20% PEG 8000, 100 mM sodium cacodylate, pH 8.0, and 200 mM calcium acetate in the presence of its substrate UDP-N-acetylglucosamine enolpyruvate. Crystals of MurB belong to the tetragonal space group P4(1)2(1)2 with a = b = 49.6 A, c = 263.2 A, and alpha = beta = gamma = 90 degrees at -160 degrees C and diffract to at least 2.5 A. Screening for heavy atom derivatives has yielded a single site that is reactive with both methylmercury nitrate and Thimerosal.
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Affiliation(s)
- T E Benson
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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26
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Dombrosky PM, Schmid MB, Young KD. Sequence divergence of the murB and rrfB genes from Escherichia coli and Salmonella typhimurium. Arch Microbiol 1994; 161:501-7. [PMID: 8048842 DOI: 10.1007/bf00307771] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The murB gene of Salmonella typhimurium was cloned and found to be 75% and 82% identical to the DNA and protein sequences, respectively, of the same gene in Escherichia coli. These identities are among the lowest recorded between the two bacteria. Nevertheless, wild-type S. typhimurium murB complemented the known temperature-sensitive E. coli mutant, and wild-type E. coli murB complemented three temperature-sensitive mutants of S. typhimurium. The 5S rRNA gene, rrfB, and the region between murB and rrfB were also cloned and sequenced. The rrfB gene of S. typhimurium differs from rrfB of E. coli in only 2 of 120 nt, but the region between murB and rrfB has diverged greatly and includes a sequence that closely resembles a repetitive extragenic palindrome of the type normally associated with E. coli. Previous comparisons of gene divergence have suggested that the chromosomal mutation rate is lower in the vicinity of the origin of replication. However, the S. typhimurium murB gene, located 6 map minutes from the origin of replication, is highly substituted at synonymous sites and the sequence between murB and rrfB is significantly modified as well. Thus, murB is an exception to the general observation that genes near the origin of replication show less divergence than do genes elsewhere in the bacterial chromosome.
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Affiliation(s)
- P M Dombrosky
- Department of Microbiology and Immunology, School of Medicine, University of North Dakota, Grand Forks 58202-9001
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27
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Chapter 3 Biosynthesis of the bacterial peptidoglycan unit. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s0167-7306(08)60406-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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28
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Abstract
A list of currently identified gene products of Escherichia coli is given, together with a bibliography that provides pointers to the literature on each gene product. A scheme to categorize cellular functions is used to classify the gene products of E. coli so far identified. A count shows that the numbers of genes concerned with small-molecule metabolism are on the same order as the numbers concerned with macromolecule biosynthesis and degradation. One large category is the category of tRNAs and their synthetases. Another is the category of transport elements. The categories of cell structure and cellular processes other than metabolism are smaller. Other subjects discussed are the occurrence in the E. coli genome of redundant pairs and groups of genes of identical or closely similar function, as well as variation in the degree of density of genetic information in different parts of the genome.
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Affiliation(s)
- M Riley
- Marine Biological Laboratory, Woods Hole, Massachusetts 02543
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29
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Doublet P, van Heijenoort J, Bohin JP, Mengin-Lecreulx D. The murI gene of Escherichia coli is an essential gene that encodes a glutamate racemase activity. J Bacteriol 1993; 175:2970-9. [PMID: 8098327 PMCID: PMC204615 DOI: 10.1128/jb.175.10.2970-2979.1993] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The murI gene of Escherichia coli was recently identified on the basis of its ability to complement the only mutant requiring D-glutamic acid for growth that had been described to date: strain WM335 of E. coli B/r (P. Doublet, J. van Heijenoort, and D. Mengin-Lecreulx, J. Bacteriol. 174:5772-5779, 1992). We report experiments of insertional mutagenesis of the murI gene which demonstrate that this gene is essential for the biosynthesis of D-glutamic acid, one of the specific components of cell wall peptidoglycan. A special strategy was used for the construction of strains with a disrupted copy of murI, because of a limited capability of E. coli strains grown in rich medium to internalize D-glutamic acid. The murI gene product was overproduced and identified as a glutamate racemase activity. UDP-N-acetylmuramoyl-L-alanine (UDP-MurNAc-L-Ala), which is the nucleotide substrate of the D-glutamic-acid-adding enzyme (the murD gene product) catalyzing the subsequent step in the pathway for peptidoglycan synthesis, appears to be an effector of the racemase activity.
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Affiliation(s)
- P Doublet
- URA 1131 du Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Orsay, France
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30
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Benson TE, Marquardt JL, Marquardt AC, Etzkorn FA, Walsh CT. Overexpression, purification, and mechanistic study of UDP-N-acetylenolpyruvylglucosamine reductase. Biochemistry 1993; 32:2024-30. [PMID: 8448160 DOI: 10.1021/bi00059a019] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The recently isolated Escherichia coli murB gene (Pucci et al., 1992) has been cloned into an expression vector and the encoded UDP-N-acetylenolpyruvylglucosamine reductase (EC 1.1.1.158) was overproduced to about 10% of soluble cell protein. The encoded 38-kDa protein has been purified to near homogeneity. It was found to be a monomer and to contain stoichiometric amounts of bound FAD which is reducible in catalytic turnover. The enzyme utilizes the 4-pro-S hydrogen of NADPH to reduce the enolpyruvyl group of UDP-N-acetylglucosamine enolpyruvate to the lactyl ether in UDP-N-acetylmuramic acid. NMR analysis of products from 2H2O and 4S-[2H]NADPH incubations establishes that a hydride from NADPH via E.FADH2 is transferred to the beta-methyl of the 3-O-lactyl moiety and a proton from solvent to the alpha-carbon of the lactyl moiety of UDP-N-acetylmuramic acid. A mechanism for this unusual enolether reduction in bacterial cell wall assembly is proposed.
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Affiliation(s)
- T E Benson
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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31
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Dougherty TJ, Thanassi JA, Pucci MJ. The Escherichia coli mutant requiring D-glutamic acid is the result of mutations in two distinct genetic loci. J Bacteriol 1993; 175:111-6. [PMID: 8093236 PMCID: PMC196103 DOI: 10.1128/jb.175.1.111-116.1993] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
D-Glutamic acid is an essential component of bacterial cell wall peptidoglycan in both gram-positive and gram-negative bacteria. Very little is known concerning the genetics and biochemistry of D-glutamate production in most bacteria, including Escherichia coli. Evidence is presented in this report for the roles of two distinct genes in E. coli WM335, a strain which is auxotrophic for D-glutamate. The first gene, which restores D-glutamate independence in WM335, was mapped, cloned, and sequenced. This gene, designated dga, is a previously reported open reading frame, located at 89.8 min on the E. coli map. The second gene, gltS, is located at 82 min. gltS encodes a protein that is involved in the transport of D- and L-glutamic acid into E. coli, and the gltS gene of WM335 was found to contain two missense mutations. To construct D-glutamate auxotrophs, it is necessary to transfer sequentially the mutated gltS locus, and then the mutated dga locus into the recipient. The sequences of the mutant forms of both dga and gltS are also presented.
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Affiliation(s)
- T J Dougherty
- Department of Microbiology, Bristol-Myers Squibb Company Pharmaceutical Research Institute, Wallingford, Connecticut 06492-7660
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32
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Doublet P, van Heijenoort J, Mengin-Lecreulx D. Identification of the Escherichia coli murI gene, which is required for the biosynthesis of D-glutamic acid, a specific component of bacterial peptidoglycan. J Bacteriol 1992; 174:5772-9. [PMID: 1355768 PMCID: PMC207102 DOI: 10.1128/jb.174.18.5772-5779.1992] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The murI gene of Escherichia coli, whose inactivation results in the inability to form colonies in the absence of D-glutamic acid, was identified in the 90-min region of the chromosome. The complementation of an auxotrophic E. coli B/r strain by various DNA sources allowed us to clone a 2.5-kbp EcoRI chromosomal fragment carrying the murI gene into multicopy plasmids. The murI gene corresponds to a previously sequenced open reading frame, ORF1 (J. Brosius, T. J. Dull, D. D. Sleeter, and H. F. Noller. J. Bacteriol. 148:107-127, 1987), located between the btuB gene, encoding the vitamin B12 outer membrane receptor protein, and the rrnB operon, which contains the genes for 16S, 23S, and 5S rRNAs. The murI gene product is predicted to be a protein of 289 amino acids with a molecular weight of 31,500. Attempts to identify its enzymatic activity were unsuccessful. Cells altered in the murI gene accumulate UDP-N-acetylmuramyl-L-alanine to a high level when depleted of D-glutamic acid. Pools of precursors located downstream in the pathway are consequently depleted, and cell lysis finally occurs when the peptidoglycan content is 25% lower than that of normally growing cells.
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Affiliation(s)
- P Doublet
- Unité de Recherche Associée 1131 du Centre National de la Recherche Scientifique, Biochimie Moléculaire et Cellulaire, Université Paris-Sud, Orsay, France
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