1
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Wiegmann D, Koppermann S, Wirth M, Niro G, Leyerer K, Ducho C. Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents. Beilstein J Org Chem 2016; 12:769-795. [PMID: 27340469 PMCID: PMC4902027 DOI: 10.3762/bjoc.12.77] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/24/2016] [Indexed: 11/23/2022] Open
Abstract
Muraymycins are a promising class of antimicrobial natural products. These uridine-derived nucleoside-peptide antibiotics inhibit the bacterial membrane protein translocase I (MraY), a key enzyme in the intracellular part of peptidoglycan biosynthesis. This review describes the structures of naturally occurring muraymycins, their mode of action, synthetic access to muraymycins and their analogues, some structure-activity relationship (SAR) studies and first insights into muraymycin biosynthesis. It therefore provides an overview on the current state of research, as well as an outlook on possible future developments in this field.
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Affiliation(s)
- Daniel Wiegmann
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66123 Saarbruecken, Germany
| | - Stefan Koppermann
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66123 Saarbruecken, Germany
| | - Marius Wirth
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66123 Saarbruecken, Germany
| | - Giuliana Niro
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66123 Saarbruecken, Germany
| | - Kristin Leyerer
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66123 Saarbruecken, Germany
| | - Christian Ducho
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66123 Saarbruecken, Germany
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2
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Barbosa MD, Smith DD. Channeling postmarketing patient data into pharmaceutical regulatory systems. Drug Discov Today 2014; 19:1897-912. [DOI: 10.1016/j.drudis.2014.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/24/2014] [Accepted: 07/24/2014] [Indexed: 12/15/2022]
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3
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Bacterial cell division proteins as antibiotic targets. Bioorg Chem 2014; 55:27-38. [PMID: 24755375 DOI: 10.1016/j.bioorg.2014.03.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 11/21/2022]
Abstract
Proteins involved in bacterial cell division often do not have a counterpart in eukaryotic cells and they are essential for the survival of the bacteria. The genetic accessibility of many bacterial species in combination with the Green Fluorescence Protein revolution to study localization of proteins and the availability of crystal structures has increased our knowledge on bacterial cell division considerably in this century. Consequently, bacterial cell division proteins are more and more recognized as potential new antibiotic targets. An international effort to find small molecules that inhibit the cell division initiating protein FtsZ has yielded many compounds of which some are promising as leads for preclinical use. The essential transglycosylase activity of peptidoglycan synthases has recently become accessible to inhibitor screening. Enzymatic assays for and structural information on essential integral membrane proteins such as MraY and FtsW involved in lipid II (the peptidoglycan building block precursor) biosynthesis have put these proteins on the list of potential new targets. This review summarises and discusses the results and approaches to the development of lead compounds that inhibit bacterial cell division.
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4
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Mann PA, Müller A, Xiao L, Pereira PM, Yang C, Ho Lee S, Wang H, Trzeciak J, Schneeweis J, dos Santos MM, Murgolo N, She X, Gill C, Balibar CJ, Labroli M, Su J, Flattery A, Sherborne B, Maier R, Tan CM, Black T, Önder K, Kargman S, Monsma FJ, Pinho MG, Schneider T, Roemer T. Murgocil is a highly bioactive staphylococcal-specific inhibitor of the peptidoglycan glycosyltransferase enzyme MurG. ACS Chem Biol 2013; 8:2442-51. [PMID: 23957438 DOI: 10.1021/cb400487f] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Modern medicine is founded on the discovery of penicillin and subsequent small molecules that inhibit bacterial peptidoglycan (PG) and cell wall synthesis. However, the discovery of new chemically and mechanistically distinct classes of PG inhibitors has become exceedingly rare, prompting speculation that intracellular enzymes involved in PG precursor synthesis are not 'druggable' targets. Here, we describe a β-lactam potentiation screen to identify small molecules that augment the activity of β-lactams against methicillin-resistant Staphylococcus aureus (MRSA) and mechanistically characterize a compound resulting from this screen, which we have named murgocil. We provide extensive genetic, biochemical, and structural modeling data demonstrating both in vitro and in whole cells that murgocil specifically inhibits the intracellular membrane-associated glycosyltransferase, MurG, which synthesizes the lipid II PG substrate that penicillin binding proteins (PBPs) polymerize and cross-link into the cell wall. Further, we demonstrate that the chemical synergy and cidality achieved between murgocil and the β-lactam imipenem is mediated through MurG dependent localization of PBP2 to the division septum. Collectively, these data validate our approach to rationally identify new target-specific bioactive β-lactam potentiation agents and demonstrate that murgocil now serves as a highly selective and potent chemical probe to assist our understanding of PG biosynthesis and cell wall biogenesis across Staphylococcal species.
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Affiliation(s)
- Paul A. Mann
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Anna Müller
- Institute
of Medical Microbiology, Immunology and Parasitology—Pharmaceutical
Microbiology Section, University of Bonn, Bonn, Germany
| | - Li Xiao
- Computational
Chemistry, Global Structure Chemistry, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Pedro M. Pereira
- Laboratory
of Bacterial Cell Biology, Instituto de Tecnologia Química
e Biológica, Universidade Nova de Lisboa, Avenida da República, 2781-901 Oeiras, Portugal
| | - Christine Yang
- Medicinal
Chemistry, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Sang Ho Lee
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Hao Wang
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Joanna Trzeciak
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Jonathan Schneeweis
- In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Margarida Moreira dos Santos
- Laboratory
of Bacterial Cell Biology, Instituto de Tecnologia Química
e Biológica, Universidade Nova de Lisboa, Avenida da República, 2781-901 Oeiras, Portugal
| | - Nicholas Murgolo
- Research
Solutions, Bioinformatics, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Xinwei She
- Informatics
IT, Merck Inc., Boston, Massachusetts 02110, United States
| | - Charles Gill
- In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Carl J. Balibar
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Marc Labroli
- Medicinal
Chemistry, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Jing Su
- Medicinal
Chemistry, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Amy Flattery
- In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Brad Sherborne
- Computational
Chemistry, Global Structure Chemistry, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Richard Maier
- Procomcure Biotech GmbH, Krems a.d. Donau, Austria
- Division of Molecular
Dermatology, Department of Dermatology, Paracelsus Medical University, Salzburg, Austria
| | - Christopher M. Tan
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Todd Black
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Kamil Önder
- Procomcure Biotech GmbH, Krems a.d. Donau, Austria
- Division of Molecular
Dermatology, Department of Dermatology, Paracelsus Medical University, Salzburg, Austria
| | - Stacia Kargman
- In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Frederick J Monsma
- In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
| | - Mariana G. Pinho
- Laboratory
of Bacterial Cell Biology, Instituto de Tecnologia Química
e Biológica, Universidade Nova de Lisboa, Avenida da República, 2781-901 Oeiras, Portugal
| | - Tanja Schneider
- Institute
of Medical Microbiology, Immunology and Parasitology—Pharmaceutical
Microbiology Section, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site
Bonn-Cologne, Bonn, Germany
| | - Terry Roemer
- Infectious
Disease Research, Merck Research Laboratories, Kenilworth, New Jersey 07033, United States
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5
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Fiuza M, Canova MJ, Patin D, Letek M, Zanella-Cléon I, Becchi M, Mateos LM, Mengin-Lecreulx D, Molle V, Gil JA. The MurC ligase essential for peptidoglycan biosynthesis is regulated by the serine/threonine protein kinase PknA in Corynebacterium glutamicum. J Biol Chem 2008; 283:36553-63. [PMID: 18974047 DOI: 10.1074/jbc.m807175200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Mur ligases play an essential role in the biosynthesis of bacterial cell-wall peptidoglycan and thus represent attractive targets for the design of novel antibacterials. These enzymes catalyze the stepwise formation of the peptide moiety of the peptidoglycan disaccharide peptide monomer unit. MurC is responsible of the addition of the first residue (L-alanine) onto the nucleotide precursor UDP-MurNAc. Phosphorylation of proteins by Ser/Thr protein kinases has recently emerged as a major physiological mechanism of regulation in prokaryotes. Herein, the hypothesis of a phosphorylation-dependent mechanism of regulation of the MurC activity was investigated in Corynebacterium glutamicum. We showed that MurC was phosphorylated in vitro by the PknA protein kinase. An analysis of the phosphoamino acid content indicated that phosphorylation exclusively occurred on threonine residues. Six phosphoacceptor residues were identified by mass spectrometry analysis, and we confirmed that mutagenesis to alanine residues totally abolished PknA-dependent phosphorylation of MurC. In vitro and in vivo ligase activity assays showed that the catalytic activity of MurC was impaired following mutation of these threonine residues. Further in vitro assays revealed that the activity of the MurC-phosphorylated isoform was severely decreased compared with the non-phosphorylated protein. To our knowledge, this is the first demonstration of a MurC ligase phosphorylation in vitro. The finding that phosphorylation is correlated with a decrease in MurC enzymatic activity could have significant consequences in the regulation of peptidoglycan biosynthesis.
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Affiliation(s)
- Maria Fiuza
- Departamento de Biología Molecular, Area de Microbiología, Facultad de Biología, Universidad de León, León 24071, Spain
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6
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Selective removal of anti-α-Gal antibodies from human serum by using synthetic α-Gal epitope on a core-shell type resin. BIOTECHNOL BIOPROC E 2008. [DOI: 10.1007/s12257-008-0141-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Schouten JA, Bagga S, Lloyd AJ, de Pascale G, Dowson CG, Roper DI, Bugg TDH. Fluorescent reagents for in vitro studies of lipid-linked steps of bacterial peptidoglycan biosynthesis: derivatives of UDPMurNAc-pentapeptide containing d-cysteine at position 4 or 5. MOLECULAR BIOSYSTEMS 2006; 2:484-91. [PMID: 17216029 DOI: 10.1039/b607908c] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UDPMurNAc-L-Ala-gamma-D-Glu-X-D-Ala-DAla (X = L-Lys or m-DAP) is the cytoplasmic precursor for the lipid-linked cycle of bacterial peptidoglycan biosynthesis, consisting of at least four enzymatic reactions, which are targets for antibacterial agents. Fluorescent derivatives of the UDPMurNAc-pentapeptide labelled at the 3rd, 4th, and 5th position of the peptide chain were prepared chemoenzymatically, in order to study the reactions catalysed by enzymes in this cycle. Derivatives labelled on the epsilon-amino group of the 3rd amino acid (N-dansyl, N-fluorescamine and N-phthalaldehyde) were prepared by chemical modification. Two methods were developed for preparation of analogues of UDPMurNAc-pentapeptide containing D-cysteine at position 4 or 5: either by MurF-catalysed ligation of the UDPMurNAc-tripeptide to synthetic D-Ala-D-Cys or D-Cys-D-Ala dipeptides; or by enzymatic synthesis of D-Ala-D-Cys by ligase VanD. D-Cys-containing UDPMurNAc-pentapeptides were labelled with pyrene maleimide, to give 4-pyrene and 5-pyrene labelled derivatives. The fluorescent UDPMurNAc-pentapeptides were processed as substrates by Escherichia coli MraY or E. coli membranes, giving 1.5-150-fold changes in fluorescence upon transformation to lipid intermediate I. Subsequent processing to lipid intermediate II gave rise only to small changes in fluorescence. Pyrene-labelled lipid intermediates I and II can be generated using Micrococcus flavus membranes, enabling the study of the later lipid-linked steps.
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Affiliation(s)
- James A Schouten
- Department of Chemistry, University of Warwick, Coventry, UK CV4 7AL
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8
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Silver LL. Does the cell wall of bacteria remain a viable source of targets for novel antibiotics? Biochem Pharmacol 2005; 71:996-1005. [PMID: 16290173 DOI: 10.1016/j.bcp.2005.10.029] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 10/13/2005] [Accepted: 10/17/2005] [Indexed: 11/19/2022]
Abstract
Whether the bacterial cell wall remains a viable source of novel antibacterials is addressed here by reviewing screen and design strategies for discovery of antibacterials with a focus on their output. Inhibitors for which antibacterial activity has been shown to be due to specific inhibition of a reaction (antibacterially validated inhibitors) are known for 8 of the 14 conserved essential steps of the pathway. Antibacterially validated enzyme inhibitors exist for six of these steps. The possible obstacles to finding validated inhibitors of the remaining enzymes are discussed and some strategies are suggested.
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting (LLC), 3403 Park Place, Springfield, NJ 07081, USA.
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9
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Ravishankar S, Kumar VP, Chandrakala B, Jha RK, Solapure SM, de Sousa SM. Scintillation proximity assay for inhibitors of Escherichia coli MurG and, optionally, MraY. Antimicrob Agents Chemother 2005; 49:1410-8. [PMID: 15793120 PMCID: PMC1068599 DOI: 10.1128/aac.49.4.1410-1418.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 09/26/2004] [Accepted: 12/27/2004] [Indexed: 11/20/2022] Open
Abstract
MurG and MraY, essential enzymes involved in the synthesis of bacterial peptidoglycan, are difficult to assay because the substrates are lipidic and hard to prepare in large quantities. Based on the use of Escherichia coli membranes lacking PBP1b, we report a high-throughput method to measure the activity of MurG and, optionally, MraY as well. In these membranes, incubation with the two peptidoglycan sugar precursors results in accumulation of lipid II rather than the peptidoglycan produced by wild-type membranes. MurG was assayed by addition of UDP-[3H]N-acetylglucosamine to membranes in which lipid I was preformed by incubation with UDP-N-acetyl-muramylpentapeptide, and the product was captured by wheat germ agglutinin scintillation proximity assay beads. In a modification of the assay, the activity of MraY was coupled to that of MurG by addition of both sugar precursors together in a single step. This allows simultaneous detection of inhibitors of either enzyme. Both assays could be performed using wild-type membranes by addition of the transglycosylase inhibitor moenomycin. Nisin and vancomycin inhibited the MurG reaction; the MraY-MurG assay was inhibited by tunicamycin as well. Inhibitors of other enzymes of peptidoglycan synthesis--penicillin G, moenomycin, and bacitracin--had no effect. Surprisingly, however, the beta-lactam cephalosporin C inhibited both the MurG and MraY-MurG assays, indicating a secondary mechanism by which this drug inhibits bacterial growth. In addition, it inhibited NADH dehydrogenase in membranes, a hitherto-unreported activity. These assays can be used to screen for novel antibacterial agents.
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Affiliation(s)
- Sudha Ravishankar
- AstraZeneca India Pvt. Ltd., Hebbal, Bellary Rd., Bangalore 560 024, India
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10
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Chantret I, Dancourt J, Barbat A, Moore SEH. Two proteins homologous to the N- and C-terminal domains of the bacterial glycosyltransferase Murg are required for the second step of dolichyl-linked oligosaccharide synthesis in Saccharomyces cerevisiae. J Biol Chem 2004; 280:9236-42. [PMID: 15615718 DOI: 10.1074/jbc.m413941200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two highly conserved eukaryotic gene products of unknown function showing homology to glycosyltransferases involved in the second steps of bacterial peptidoglycan (Murg) and capsular polysaccharide (Cps14f/Cps14g) biosynthesis have been identified in silico. The amino acid sequence of the eukaryotic protein that is homologous to the lipid acceptor- and membrane-associating N-terminal domain of Murg and the Cps14f beta4-galactosyltransferase enhancer protein is predicted to possess a cleavable signal peptide and transmembrane helices. The other eukaryotic protein is predicted to possess neither transmembrane regions nor a signal peptide but is homologous to the UDP-sugar binding C-terminal domain of Murg and the Cps14g beta4-galactosyltransferase. Both the eukaryotic proteins are encoded by essential genes in Saccharomyces cerevisiae, and down-regulation of either causes growth retardation, reduced N-glycosylation of carboxypeptidase Y, and accumulation of dolichyl-PP-GlcNAc. In vitro studies demonstrate that these proteins are required for transfer of [3H]GlcNAc from UDP-[3H]GlcNAc onto dolichyl-PP-GlcNAc. To conclude, two gene products showing homology to bacterial glycosyltransferases are required for the second step in dolichyl-PP-oligosaccharide biosynthesis.
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Affiliation(s)
- Isabelle Chantret
- Institut National de la Santé et de la Recherche Médicale, U504, Bâtiment INSERM, 16 avenue Paul Vaillant-Couturier, 94807 Villejuif, France
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11
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Chan PF, Holmes DJ, Payne DJ. Finding the gems using genomic discovery: antibacterial drug discovery strategies – the successes and the challenges. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ddstr.2004.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Ramos A, Honrubia MP, Vega D, Ayala JA, Bouhss A, Mengin-Lecreulx D, Gil JA. Characterization and chromosomal organization of the murD-murC-ftsQ region of Corynebacterium glutamicum ATCC 13869. Res Microbiol 2004; 155:174-84. [PMID: 15059630 DOI: 10.1016/j.resmic.2003.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Accepted: 11/20/2003] [Indexed: 11/28/2022]
Abstract
The sequence of a 4.6-kb region of DNA from Corynebacterium glutamicum ATCC 13869 lying upstream from the ftsQ-ftsZ region has been determined. The region contains four genes with high similarity to the murD, ftsW, murG, and murC genes from different microorganisms. The products of these mur genes probably catalyse several steps in the formation of the precursors for peptidoglycan synthesis in C. glutamicum, whereas ftsW might play also a role in the stabilisation of the FtsZ ring during cell division. The murC gene product was purified to near homogeneity and its UDP-N-acetylmuramate: L-alanine adding activity was demonstrated. Northern analysis indicated that ftsW, murG and ftsQ are poorly expressed in C. glutamicum whereas murC and ftsZ are expressed at higher levels at the beginning of the exponential phase. Dicistronic (ftsQ-ftsZ) and monocistronic (murC and ftsZ) transcripts can be detected using specific probes and are in agreement with the lack of transcriptional terminators in the partially analysed dcw cluster. Disruption experiments performed in C. glutamicum using internal fragments of the ftsW, murG and murC genes allowed us to conclude that FtsW, MurG, and MurC are essential gene products in C. glutamicum.
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MESH Headings
- Base Sequence
- Blotting, Northern
- Cell Wall/genetics
- Cell Wall/metabolism
- Chromosome Mapping
- Cloning, Molecular
- Corynebacterium/enzymology
- Corynebacterium/genetics
- Corynebacterium/metabolism
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- Genes, Bacterial/genetics
- Genes, Bacterial/physiology
- Genes, Essential/physiology
- Genetic Complementation Test
- Molecular Sequence Data
- Mutagenesis, Insertional
- Plasmids
- Polymerase Chain Reaction
- Sequence Analysis, DNA
- Transformation, Genetic
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Affiliation(s)
- Angelina Ramos
- Area de Microbiología, Departamento de Ecología, Genética y Microbiología, Facultad de Biología, Universidad de León, 24071 León, Spain
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13
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Stachyra T, Dini C, Ferrari P, Bouhss A, van Heijenoort J, Mengin-Lecreulx D, Blanot D, Biton J, Le Beller D. Fluorescence detection-based functional assay for high-throughput screening for MraY. Antimicrob Agents Chemother 2004; 48:897-902. [PMID: 14982781 PMCID: PMC353143 DOI: 10.1128/aac.48.3.897-902.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have developed a novel assay specific to MraY, which catalyzes the first membrane step in the biosynthesis of bacterial cell wall peptidoglycan. This was accomplished by using UDP-MurNAc-N(epsilon)-dansylpentapeptide, a fluorescent derivative of the MraY nucleotide substrate, and a partially purified preparation of MraY solubilized from membranes of an Escherichia coli overproducing strain. Two versions of the assay were developed, one consisting of the high-pressure liquid chromatography separation of the substrate and product (dansylated lipid I) and the other, without separation and adapted to the high-throughput format, taking advantage of the different fluorescence properties of the nucleotide and lipid I in the reaction medium. The latter assay was validated with a set of natural and synthetic MraY inhibitors.
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14
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Lloyd AJ, Brandish PE, Gilbey AM, Bugg TDH. Phospho-N-acetyl-muramyl-pentapeptide translocase from Escherichia coli: catalytic role of conserved aspartic acid residues. J Bacteriol 2004; 186:1747-57. [PMID: 14996806 PMCID: PMC355978 DOI: 10.1128/jb.186.6.1747-1757.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phospho-N-acetyl-muramyl-pentapeptide translocase (translocase 1) catalyzes the first of a sequence of lipid-linked steps that ultimately assemble the peptidoglycan layer of the bacterial cell wall. This essential enzyme is the target of several natural product antibiotics and has recently been the focus of antimicrobial drug discovery programs. The catalytic mechanism of translocase 1 is believed to proceed via a covalent intermediate formed between phospho-N-acetyl-muramyl-pentapeptide and a nucleophilic amino acid residue. Amino acid sequence alignments of the translocase 1 family and members of the related transmembrane phosphosugar transferase superfamily revealed only three conserved residues that possess nucleophilic side chains: the aspartic acid residues D115, D116, and D267. Here we report the expression and partial purification of Escherichia coli translocase 1 as a C-terminal hexahistidine (C-His6) fusion protein. Three enzymes with the site-directed mutations D115N, D116N, and D267N were constructed, expressed, and purified as C-His6 fusions. Enzymatic analysis established that all three mutations eliminated translocase 1 activity, and this finding verified the essential role of these residues. By analogy with the structural environment of the double aspartate motif found in prenyl transferases, we propose a model whereby D115 and D116 chelate a magnesium ion that coordinates with the pyrophosphate bridge of the UDP-N-acetyl-muramyl-pentapeptide substrate and in which D267 therefore fulfills the role of the translocase 1 active-site nucleophile.
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Affiliation(s)
- Adrian J Lloyd
- Department of Chemistry, University of Warwick, Coventry, United Kingdom
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15
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Chandrakala B, Shandil RK, Mehra U, Ravishankar S, Kaur P, Usha V, Joe B, deSousa SM. High-throughput screen for inhibitors of transglycosylase and/or transpeptidase activities of Escherichia coli penicillin binding protein 1b. Antimicrob Agents Chemother 2004; 48:30-40. [PMID: 14693515 PMCID: PMC310179 DOI: 10.1128/aac.48.1.30-40.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Penicillin binding protein (PBP) 1b of Escherichia coli has both transglycosylase and transpeptidase activities, which are attractive targets for the discovery of new antibacterial agents. A high-throughput assay that detects inhibitors of the PBPs was described previously, but it cannot distinguish them from inhibitors of the MraY, MurG, and lipid pyrophosphorylase. We report on a method that distinguishes inhibitors of both activities of the PBPs from those of the other three enzymes. Radioactive peptidoglycan was synthesized by using E. coli membranes. Following termination of the reaction the products were analyzed in three ways. Wheat germ agglutinin (WGA)-coated scintillation proximity assay (SPA) beads were added to one set, and the same beads together with a detergent were added to a second set. Type A polyethylenimine-coated WGA-coated SPA beads were added to a third set. By comparison of the results of assays run in parallel under the first two conditions, inhibitors of the transpeptidase and transglycosylase could be distinguished from inhibitors of the other enzymes, as the inhibitors of the other enzymes showed similar inhibitory concentrations (IC(50)s) under both conditions but the inhibitors of the PBPs showed insignificant inhibition in the absence of detergent. Furthermore, comparison of the results of assays run under conditions two and three enabled the distinction of transpeptidase inhibitors. Penicillin and other beta-lactams showed insignificant inhibition with type A beads compared with that shown with WGA-coated SPA beads plus detergent. However, inhibitors of the other four enzymes (tunicamycin, nisin, bacitracin, and moenomycin) showed similar IC(50)s under both conditions. We show that the main PBP being measured under these conditions is PBP 1b. This screen can be used to find novel transglycosylase or transpeptidase inhibitors.
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Affiliation(s)
- B Chandrakala
- AstraZeneca India Pvt. Ltd., Bangalore 560 024, India
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16
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van den Brink-van der Laan E, Boots JWP, Spelbrink REJ, Kool GM, Breukink E, Killian JA, de Kruijff B. Membrane interaction of the glycosyltransferase MurG: a special role for cardiolipin. J Bacteriol 2003; 185:3773-9. [PMID: 12813070 PMCID: PMC161595 DOI: 10.1128/jb.185.13.3773-3779.2003] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MurG is a peripheral membrane protein that is one of the key enzymes in peptidoglycan biosynthesis. The crystal structure of Escherichia coli MurG (S. Ha, D. Walker, Y. Shi, and S. Walker, Protein Sci. 9:1045-1052, 2000) contains a hydrophobic patch surrounded by basic residues that may represent a membrane association site. To allow investigation of the membrane interaction of MurG on a molecular level, we expressed and purified MurG from E. coli in the absence of detergent. Surprisingly, we found that lipid vesicles copurify with MurG. Freeze fracture electron microscopy of whole cells and lysates suggested that these vesicles are derived from vesicular intracellular membranes that are formed during overexpression. This is the first study which shows that overexpression of a peripheral membrane protein results in formation of additional membranes within the cell. The cardiolipin content of cells overexpressing MurG was increased from 1 +/- 1 to 7 +/- 1 mol% compared to nonoverexpressing cells. The lipids that copurify with MurG were even further enriched in cardiolipin (13 +/- 4 mol%). MurG activity measurements of lipid I, its natural substrate, incorporated in pure lipid vesicles showed that the MurG activity is higher for vesicles containing cardiolipin than for vesicles with phosphatidylglycerol. These findings support the suggestion that MurG interacts with phospholipids of the bacterial membrane. In addition, the results show a special role for cardiolipin in the MurG-membrane interaction.
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Affiliation(s)
- Els van den Brink-van der Laan
- Department Biochemistry of Membranes, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, 3584 CH, Utrecht, The Netherlands.
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Auger G, van Heijenoort J, Mengin-Lecreulx D, Blanot D. A MurG assay which utilises a synthetic analogue of lipid I. FEMS Microbiol Lett 2003; 219:115-9. [PMID: 12594032 DOI: 10.1016/s0378-1097(02)01203-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A standard assay for the MurG enzyme using a lipid I analogue [MurNAc(N(epsilon)-dansylpentapeptide)-pyrophosphoryl (R,S)-alpha-dihydroheptaprenol] and radioactive UDP-N-acetylglucosamine was set up. A high concentration (35%) of dimethylsulfoxide was necessary for maximal activity. Separation and quantitation were accomplished by reverse-phase high performance liquid chromatography (HPLC) in isocratic conditions and on-line radioactivity detection, thereby providing a rapid and accurate assay. The kinetic parameters of the MurG reaction were determined; the reaction was shown to also catalyse the reverse reaction at a measurable rate. A lipid I analogue containing dihydroundecaprenol as the prenyl chain turned out to be a poor MurG substrate, presumably owing to aggregation.
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Affiliation(s)
- Geneviève Auger
- Enveloppes Bactériennes et Antibiotiques, UMR 8619 du CNRS, Bâtiment 430, Université de Paris-Sud, 91405, Orsay, France
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