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Gupta R, Singh M, Pathania R. Chemical genetic approaches for the discovery of bacterial cell wall inhibitors. RSC Med Chem 2023; 14:2125-2154. [PMID: 37974958 PMCID: PMC10650376 DOI: 10.1039/d3md00143a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 08/10/2023] [Indexed: 11/19/2023] Open
Abstract
Antimicrobial resistance (AMR) in bacterial pathogens is a worldwide health issue. The innovation gap in discovering new antibiotics has remained a significant hurdle in combating the AMR problem. Currently, antibiotics target various vital components of the bacterial cell envelope, nucleic acid and protein biosynthesis machinery and metabolic pathways essential for bacterial survival. The critical role of the bacterial cell envelope in cell morphogenesis and integrity makes it an attractive drug target. While a significant number of in-clinic antibiotics target peptidoglycan biosynthesis, several components of the bacterial cell envelope have been overlooked. This review focuses on various antibacterial targets in the bacterial cell wall and the strategies employed to find their novel inhibitors. This review will further elaborate on combining forward and reverse chemical genetic approaches to discover antibacterials that target the bacterial cell envelope.
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Affiliation(s)
- Rinki Gupta
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee Roorkee - 247 667 Uttarakhand India
| | - Mangal Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee Roorkee - 247 667 Uttarakhand India
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee Roorkee - 247 667 Uttarakhand India
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2
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Mitachi K, Yun HG, Gillman CD, Skorupinska-Tudek K, Swiezewska E, Clemons WM, Kurosu M. Substrate Tolerance of Bacterial Glycosyltransferase MurG: Novel Fluorescence-Based Assays. ACS Infect Dis 2020; 6:1501-1516. [PMID: 31769280 DOI: 10.1021/acsinfecdis.9b00242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
MurG (uridine diphosphate-N-acetylglucosamine/N-acetylmuramyl-(pentapeptide) pyrophosphoryl-undecaprenol N-acetylglucosamine transferase) is an essential bacterial glycosyltransferase that catalyzes the N-acetylglucosamine (GlcNAc) transformation of lipid I to lipid II during peptidoglycan biosynthesis. Park's nucleotide has been a convenient biochemical tool to study the function of MraY (phospho-MurNAc-(pentapeptide) translocase) and MurG; however, no fluorescent probe has been developed to differentiate individual processes in the biotransformation of Park's nucleotide to lipid II via lipid I. Herein, we report a robust assay of MurG using either the membrane fraction of a M. smegmatis strain or a thermostable MraY and MurG of Hydrogenivirga sp. as enzyme sources, along with Park's nucleotide or Park's nucleotide-Nε-C6-dansylthiourea and uridine diphosphate (UDP)-GlcN-C6-FITC as acceptor and donor substrates. Identification of both the MraY and MurG products can be performed simultaneously by HPLC in dual UV mode. Conveniently, the generated lipid II fluorescent analogue can also be quantitated via UV-Vis spectrometry without the separation of the unreacted lipid I derivative. The microplate-based assay reported here is amenable to high-throughput MurG screening. A preliminary screening of a collection of small molecules has demonstrated the robustness of the assays and resulted in rediscovery of ristocetin A as a strong antimycobacterial MurG and MraY inhibitor.
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Affiliation(s)
- Katsuhiko Mitachi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
| | - Hyun Gi Yun
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, United States
| | - Cody D. Gillman
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, United States
| | - Karolina Skorupinska-Tudek
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Ewa Swiezewska
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - William M. Clemons
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, United States
| | - Michio Kurosu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
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3
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The Membrane Steps of Bacterial Cell Wall Synthesis as Antibiotic Targets. Antibiotics (Basel) 2016; 5:antibiotics5030028. [PMID: 27571111 PMCID: PMC5039524 DOI: 10.3390/antibiotics5030028] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 11/23/2022] Open
Abstract
Peptidoglycan is the major component of the cell envelope of virtually all bacteria. It has structural roles and acts as a selective sieve for molecules from the outer environment. Peptidoglycan synthesis is therefore one of the most important biogenesis pathways in bacteria and has been studied extensively over the last twenty years. The pathway starts in the cytoplasm, continues in the cytoplasmic membrane and finishes in the periplasmic space, where the precursor is polymerized into the peptidoglycan layer. A number of proteins involved in this pathway, such as the Mur enzymes and the penicillin binding proteins (PBPs), have been studied and regarded as good targets for antibiotics. The present review focuses on the membrane steps of peptidoglycan synthesis that involve two enzymes, MraY and MurG, the inhibitors of these enzymes and the inhibition mechanisms. We also discuss the challenges of targeting these two cytoplasmic membrane (associated) proteins in bacterial cells and the perspectives on how to overcome the issues.
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4
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Mitachi K, Siricilla S, Yang D, Kong Y, Skorupinska-Tudek K, Swiezewska E, Franzblau SG, Kurosu M. Fluorescence-based assay for polyprenyl phosphate-GlcNAc-1-phosphate transferase (WecA) and identification of novel antimycobacterial WecA inhibitors. Anal Biochem 2016; 512:78-90. [PMID: 27530653 DOI: 10.1016/j.ab.2016.08.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/18/2016] [Accepted: 08/08/2016] [Indexed: 11/26/2022]
Abstract
Polyprenyl phosphate-GlcNAc-1-phosphate transferase (WecA) is an essential enzyme for the growth of Mycobacterium tuberculosis (Mtb) and some other bacteria. Mtb WecA catalyzes the transformation from UDP-GlcNAc to decaprenyl-P-P-GlcNAc, the first membrane-anchored glycophospholipid that is responsible for the biosynthesis of mycolylarabinogalactan in Mtb. Inhibition of WecA will block the entire biosynthesis of essential cell wall components of Mtb in both replicating and non-replicating states, making this enzyme a target for development of novel drugs. Here, we report a fluorescence-based method for the assay of WecA using a modified UDP-GlcNAc, UDP-Glucosamine-C6-FITC (1), a membrane fraction prepared from an M. smegmatis strain, and the E. coli B21WecA. Under the optimized conditions, UDP-Glucosamine-C6-FITC (1) can be converted to the corresponding decaprenyl-P-P-Glucosamine-C6-FITC (3) in 61.5% yield. Decaprenyl-P-P-Glucosamine-C6-FITC is readily extracted with n-butanol and can be quantified by ultraviolet-visible (UV-vis) spectrometry. Screening of the compound libraries designed for bacterial phosphotransferases resulted in the discovery of a selective WecA inhibitor, UT-01320 (12) that kills both replicating and non-replicating Mtb at low concentration. UT-01320 (12) also kills the intracellular Mtb in macrophages. We conclude that the WecA assay reported here is amenable to medium- and high-throughput screening, thus facilitating the discovery of novel WecA inhibitors.
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Affiliation(s)
- Katsuhiko Mitachi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
| | - Shajila Siricilla
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
| | - Dong Yang
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, 858 Madison Avenue, Memphis, TN 38163-0001, United Sates
| | - Ying Kong
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Science Center, 858 Madison Avenue, Memphis, TN 38163-0001, United Sates
| | - Karolina Skorupinska-Tudek
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Ewa Swiezewska
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Scott G Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL 60612, United States
| | - Michio Kurosu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States.
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5
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Gene expression analysis for Listeria monocytogenes following exposure to pulsed light and continuous ultraviolet light treatments. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2016.01.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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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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7
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Moberg A, Zander Balderud L, Hansson E, Boyd H. Assessing HTS performance using BioAssay Ontology: screening and analysis of a bacterial phospho-N-acetylmuramoyl-pentapeptide translocase campaign. Assay Drug Dev Technol 2015; 12:506-13. [PMID: 25415593 DOI: 10.1089/adt.2014.595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
With the public availability of biochemical assays and screening data constantly increasing, new applications for data mining and method analysis are evolving in parallel. One example is BioAssay Ontology (BAO) for systematic classification of assays based on screening setup and metadata annotations. In this article we report a high-throughput screening (HTS) against phospho-N-acetylmuramoyl-pentapeptide translocase (MraY), an attractive antibacterial drug target involved in peptidoglycan synthesis. The screen resulted in novel chemistry identification using a fluorescence resonance energy transfer assay. To address a subset of the false positive hits, a frequent hitter analysis was performed using an approach in which MraY hits were compared with hits from similar assays, previously used for HTS. The MraY assay was annotated according to BAO and three internal reference assays, using a similar assay design and detection technology, were identified. Analyzing the assays retrospectively, it was clear that both MraY and the three reference assays all showed a high false positive rate in the primary HTS assays. In the case of MraY, false positives were efficiently identified by applying a method to correct for compound interference at the hit-confirmation stage. Frequent hitter analysis based on the three reference assays with similar assay method identified additional false actives in the primary MraY assay as frequent hitters. This article demonstrates how assays annotated using BAO terms can be used to identify closely related reference assays, and that analysis based on these assays clearly can provide useful data to influence assay design, technology, and screening strategy.
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Affiliation(s)
- Andreas Moberg
- 1 Screening Sciences , Discovery Sciences, AstraZeneca, Mölndal, Sweden
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8
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Siricilla S, Mitachi K, Skorupinska-Tudek K, Swiezewska E, Kurosu M. Biosynthesis of a water-soluble lipid I analogue and a convenient assay for translocase I. Anal Biochem 2014; 461:36-45. [PMID: 24939461 DOI: 10.1016/j.ab.2014.05.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 05/08/2014] [Accepted: 05/22/2014] [Indexed: 02/07/2023]
Abstract
Translocase I (MraY/MurX) is an essential enzyme in growth of the vast majority of bacteria that catalyzes the transformation from UDP-MurNAc-pentapeptide (Park's nucleotide) to prenyl-MurNAc-pentapeptide (lipid I), the first membrane-anchored peptidoglycan precursor. MurX has received considerable attention in the development of new tuberculosis (TB) drugs due to the fact that the MurX inhibitors kill exponentially growing Mycobacterium tuberculosis (Mtb) much faster than clinically used TB drugs. Lipid I isolated from Mtb contains the C50-prenyl unit that shows very poor water solubility; thus, this chemical characteristic of lipid I renders MurX enzyme assays impractical for screening and lacks reproducibility of the enzyme assays. We have established a scalable chemical synthesis of Park's nucleotide-N(ε)-dansylthiourea 2 that can be used as a MurX enzymatic substrate to form lipid I analogues. In our investigation of the minimum structure requirement of the prenyl phosphate in the MraY/MurX-catalyzed lipid I analogue synthesis with 2, we found that neryl phosphate (C10 phosphate) can be recognized by MraY/MurX to generate the water-soluble lipid I analogue in quantitative yield under the optimized conditions. Here, we report a rapid and robust analytical method for quantifying MraY/MurX inhibitory activity of library molecules.
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Affiliation(s)
- Shajila Siricilla
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
| | - Katsuhiko Mitachi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
| | - Karolina Skorupinska-Tudek
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Ewa Swiezewska
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Michio Kurosu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN 38163-0001, United States
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9
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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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Jha RK, Katagihallimath N, Hota SK, Das KS, de Sousa SM. An assay for exogenous sources of purified MurG, enabled by the complementation of Escherichia coli murG(Ts) by the Mycobacterium tuberculosis homologue. FEMS Microbiol Lett 2011; 326:161-7. [DOI: 10.1111/j.1574-6968.2011.02446.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 09/30/2011] [Accepted: 10/18/2011] [Indexed: 11/29/2022] Open
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Abstract
This review is an attempt to bring together and critically evaluate the now-abundant but dispersed data concerning the lipid intermediates of the biosynthesis of bacterial peptidoglycan. Lipid I, lipid II, and their modified forms play a key role not only as the specific link between the intracellular synthesis of the peptidoglycan monomer unit and the extracytoplasmic polymerization reactions but also in the attachment of proteins to the bacterial cell wall and in the mechanisms of action of antibiotics with which they form specific complexes. The survey deals first with their detection, purification, structure, and preparation by chemical and enzymatic methods. The recent important advances in the study of transferases MraY and MurG, responsible for the formation of lipids I and II, are reported. Various modifications undergone by lipids I and II are described, especially those occurring in gram-positive organisms. The following section concerns the cellular location of the lipid intermediates and the translocation of lipid II across the cytoplasmic membrane. The great efforts made since 2000 in the study of the glycosyltransferases catalyzing the glycan chain formation with lipid II or analogues are analyzed in detail. Finally, examples of antibiotics forming complexes with the lipid intermediates are presented.
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12
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Kurosu M, Mahapatra S, Narayanasamy P, Crick DC. Chemoenzymatic synthesis of Park’s nucleotide: toward the development of high-throughput screening for MraY inhibitors. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2006.11.160] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ramachandran V, Chandrakala B, Kumar VP, Usha V, Solapure SM, de Sousa SM. Screen for inhibitors of the coupled transglycosylase-transpeptidase of peptidoglycan biosynthesis in Escherichia coli. Antimicrob Agents Chemother 2006; 50:1425-32. [PMID: 16569861 PMCID: PMC1426922 DOI: 10.1128/aac.50.4.1425-1432.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2005] [Revised: 01/11/2006] [Accepted: 02/03/2006] [Indexed: 11/20/2022] Open
Abstract
Class A high-molecular-weight penicillin-binding protein 1a (PBP1a) and PBP1b of Escherichia coli have both transglycosylase (TG) and transpeptidase (TP) activity. These enzymes are difficult to assay, since their substrates are difficult to prepare. We show the activity of PBP1a or PBP1b can be measured in membranes by cloning the PBP into an E. coli ponB::Spcr strain. Using this assay, we show that PBP1a is approximately 10-fold more sensitive to penicillin than PBP1b and that the 50% inhibitory concentration (IC50) of moenomycin, a TG inhibitor, is approximately 10-fold higher in the PBP transformants than in wild-type membranes; this increase in IC50 in transformants can be used to test the specificity of test compounds for inhibition of the TG. Alternatively, the coupled TG-TP activity of PBP1b can be directly measured in a two-step microplate assay. In the first step, radiolabeled lipid II, the TG substrate, was made in membranes of the E. coli ponB::Spcr strain by incubation with the peptidoglycan sugar precursors. In the second step, the TG-TP activity was assayed by adding a source of PBP1b to the membranes. The coupled TG-TP activity converts lipid II to cross-linked peptidoglycan, which was specifically captured by wheat germ agglutinin-coated scintillation proximity beads in the presence of 0.2% Sarkosyl (B. Chandrakala et al., Antimicrob. Agents Chemother. 48:30-40, 2004). The TG-TP assay was inhibited by penicillin and moenomycin as expected. Surprisingly, tunicamycin and nisin also inhibited the assay, and paper chromatography analysis revealed that both inhibited the transglycosylase. The assay can be used to screen for novel antibacterial agents.
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14
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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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15
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Solapure SM, Raphael P, Gayathri CN, Barde SP, Chandrakala B, Das KS, De Sousa SM. Development of a microplate-based scintillation proximity assay for MraY using a modified substrate. ACTA ACUST UNITED AC 2005; 10:149-56. [PMID: 15799958 DOI: 10.1177/1087057104272007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
MraY is an established target for the discovery of antibacterial agents. The conventional assay for MraY uses radioactive substrate and analysis of products after paper chromatography or butanol extraction. Synthesis of radiolabeled substrate has been done in vitro using purified enzymes or by growing cells on radiolabeled precursors. The authors report a simple and rapid method to chemically radiolabel MraY substrate, UDP-MurNAc-pentapeptide. Specific activity obtained by this method was more than 100 times higher than the conventionally labeled substrate, and yields are high enough to support the requirements of high-throughput screening (HTS). The authors have developed a microplate-based homogeneous assay for MraY in which the product is captured on wheat germ agglutinin (WGA) scintillation proximity assay (SPA) beads. The assay was validated by showing inhibition by specific inhibitors of MraY but not by inhibitors of other enzymes of peptidoglycan synthesis. The assay uses wild-type membranes of Escherichia coli, giving it an advantage over recently described assays that need the protein to be overexpressed. In addition, it has an advantage over the high-throughput MraY-MurG coupled assay reported in the literature because it is MraY specific, and therefore hits obtained in this assay do not need further deconvolution. It has potential for use in HTS approaches to find novel inhibitors of MraY.
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Affiliation(s)
- S M Solapure
- AstraZeneca India Pvt. Ltd., Bellary Road, Hebbal, Bangalore, India.
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16
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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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17
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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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18
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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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19
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Hyland SA, Anderson MS. A high-throughput solid-phase extraction assay capable of measuring diverse polyprenyl phosphate: sugar-1-phosphate transferases as exemplified by the WecA, MraY, and MurG proteins. Anal Biochem 2003; 317:156-65. [PMID: 12758253 DOI: 10.1016/s0003-2697(03)00088-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The bacterial proteins WecA and MraY are members of the polyprenyl phosphate:N-acetylhexosamine-1-phosphate transferase family, each of which catalyzes the transfer of a specific hexosamine 1-P from a soluble UDP-hexosamine substrate to a bactoprenyl phosphate carrier at the membrane surface. Currently, assays designed to quantitate the activity of these enzymes rely on paper chromatography or liquid-liquid extractions or are specialized to a few members of the family. We describe a generalizable, high-throughput, one-pot assay for these activities that uses a solid-liquid bead-based separation system to selectively adsorb the highly hydrophobic products of reaction. By judicious choice of radiolabeled UDP-hexosamine precursor, the same format can be used to quantitate not only diverse members of this transferase family, but also enzymes that catalyze the further modification of these transferase products. This possibility is exemplified by the MurG protein of bacterial cell wall synthesis, which catalyzes the addition of an N-acetylglucosamine residue to the product of the MraY reaction. Thus, the use of this flexible assay tool will allow a critical biochemical and enzymologic analysis of many such membrane-bound transferases in a similar setting.
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Affiliation(s)
- Sheryl A Hyland
- Department of Atherosclerosis and Endocrinology, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA
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20
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Zawadzke LE, Wu P, Cook L, Fan L, Casperson M, Kishnani M, Calambur D, Hofstead SJ, Padmanabha R. Targeting the MraY and MurG bacterial enzymes for antimicrobial therapeutic intervention. Anal Biochem 2003; 314:243-52. [PMID: 12654311 DOI: 10.1016/s0003-2697(02)00622-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Assays for two enzymes from Escherichia coli were developed and validated as antibacterial inhibitor screens. The MraY and MurG enzymes were overexpressed and purified as the membrane fraction or to homogeneity, respectively. The MurG enzyme was expressed with a six-histidine tag using an optimized minimal-medium protocol for subsequent purification. Although traditional assays were established, the enzymes were also assayed via a 96-well membrane plate assay and a 384-well scintillation proximity-based assay developed herein. These assays afford a more economical and high-throughput evaluation of inhibitors. A mureidomycin inhibitor mix was used as a control for the assay development and screen validation. Several inhibitors resulting from a high-throughput screen were found and evaluated for potential therapeutic use.
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Affiliation(s)
- Laura E Zawadzke
- Pharmaceutical Research Institute, Bristol-Myers Squibb, Wallingford, CT 06492-7660, USA
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21
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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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22
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Barbosa MDFS, Ross HO, Hillman MC, Meade RP, Kurilla MG, Pompliano DL. A multitarget assay for inhibitors of membrane-associated steps of peptidoglycan biosynthesis. Anal Biochem 2002; 306:17-22. [PMID: 12069409 DOI: 10.1006/abio.2001.5691] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peptidoglycan synthesis begins in the cytoplasm with the condensation of UDP-N-acetyl glucosamine (UDP-GlcNAc) and phosphoenolpyruvate catalyzed by UDP-N-acetylglucosamine enolpyruvoyl transferase. UDP-GlcNAc is also utilized as substrate for the glycosyltransferase MurG, a membrane-bound enzyme that catalyzes the production of lipid II. Membranes from Escherichia coli cells overproducing MurG support peptidoglycan formation at a rate approximately fivefold faster than membranes containing wild-type levels of MurG. Conditions have been optimized for the production of large amounts of membranes with increased levels of MurG, allowing the development of an assay suitable for high-throughput screening of large compound libraries. The quality of the purified membranes was assessed by electron microscopy and also by testing cross-linked peptidoglycan production. Moreover, kinetic studies allowed the determination of optimal concentrations of the substrates and membranes to be utilized for maximum sensitivity of the assay. Using a 96-well assay format, the IC50 values for vancomycin, tunicamycin, flavomycin, and bacitracin were 1.1 microM, 0.01 microg/ml, 0.03 microg/ml, and 0.7 microg/ml, respectively.
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Affiliation(s)
- Maria D F S Barbosa
- Department of Antimicrobial Research, Bristol-Myers Squibb Pharmaceuticals, Wilmington, Delaware 19880, USA.
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23
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Barbosa MDFS, Yang G, Fang J, Kurilla MG, Pompliano DL. Development of a whole-cell assay for peptidoglycan biosynthesis inhibitors. Antimicrob Agents Chemother 2002; 46:943-6. [PMID: 11897573 PMCID: PMC127110 DOI: 10.1128/aac.46.4.943-946.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2001] [Accepted: 12/31/2001] [Indexed: 11/20/2022] Open
Abstract
Osmotically stabilized Escherichia coli cells subjected to freezing and thawing were utilized as the source of enzymes for a peptidoglycan pathway assay that can be used to simultaneously test all targets of the committed steps of cell wall biosynthesis. The use of (14)C-labeled UDP-N-acetylglucosamine (UDP-GlcNAc) as a substrate allows the direct detection of cross-linked peptidoglycan formed. The assay was validated with known antibiotics. Fosfomycin was the strongest inhibitor of the pathway assay, with a 50% inhibitory concentration of 1 microM. Flavomycin, bacitracin, vancomycin, D-cycloserine, penicillin G, and ampicillin also inhibited formation of radiolabeled peptidoglycan by the E. coli cells. Screening of compounds identified two inhibitors of the pathway, Cpd1 and Cpd2. Subsequent tests with a biochemical assay utilizing purified enzyme implicated UDP-GlcNAc enolpyruvyl transferase (MurA) as the target of Cpd1. This compound inhibits the first enzyme of the pathway in a time-dependent manner. Moreover, enzyme inactivation is dependent on preincubation in the presence of UDP-GlcNAc, which forms a complex with MurA, exposing its active site. Cpd1 also displayed antimicrobial activity against a panel of microorganisms. The pathway assay used in conjunction with assays for individual enzymes provides an efficient means of detecting and characterizing novel antimicrobial agents.
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Affiliation(s)
- Maria D F S Barbosa
- Department of Antimicrobial Research, Bristol-Myers Squibb Pharma, Wilmington, Delaware 19880, USA.
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24
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Abstract
This review focuses on target-based approaches for developing new chemical classes of antibacterial agents aimed at the bacterial cell wall. The clinical success of antibiotics such as beta-lactams and glycopeptides validates this chemotherapeutic strategy and emerging resistance to these agents warrants the development of new antibacterial drugs. Understanding the mechanism of action and resistance to beta-lactams and glycopeptides at a molecular level has supported the development of new agents that prevent transpeptidation and transglycosylation reactions of peptidoglycan polymerisation. The enzymes involved in the synthesis of the peptidoglycan structural unit have also been targeted for antibacterial discovery. The influence of bacterial genetics and genomics, structural biology, assay development and the properties of known inhibitors on these approaches will be discussed in the context of drug discovery.
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Affiliation(s)
- David W Green
- Cubist Pharmaceuticals, Inc., 65 Hayden Ave., Lexington, MA 02421, USA.
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25
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Cudic P, Behenna DC, Yu MK, Kruger RG, Szewczuk LM, McCafferty DG. Synthesis of P(1)-Citronellyl-P(2)-alpha-D-pyranosyl pyrophosphates as potential substrates for the E. coli undecaprenyl-pyrophosphoryl-N-acetylglucoseaminyl transferase MurG. Bioorg Med Chem Lett 2001; 11:3107-10. [PMID: 11720853 DOI: 10.1016/s0960-894x(01)00653-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
P(1)-Citronellyl-P(2)-alpha-D-pyranosyl pyrophosphates containing alpha-D-N-acetylglucoseaminyl, alpha-D-glucosyl, and alpha-D-N-acetylmuramyl carbohydrates were synthesized and used in substrate specificity studies of the Escherichia coli MurG enzyme. Oxalyl chloride activation of citronellyl phosphate for coupling to alpha-D-pyranose-1-phosphates resulted in markedly improved yields over traditional Khorana-Moffatt and diphenyl chlorophosphate activation strategies.
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Affiliation(s)
- P Cudic
- Johnson Research Foundation and the Department of Biochemistry and Biophysics, The University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6059, USA
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26
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Chandrakala B, Elias BC, Mehra U, Umapathy NS, Dwarakanath P, Balganesh TS, deSousa SM. Novel scintillation proximity assay for measuring membrane-associated steps of peptidoglycan biosynthesis in Escherichia coli. Antimicrob Agents Chemother 2001; 45:768-75. [PMID: 11181358 PMCID: PMC90371 DOI: 10.1128/aac.45.3.768-775.2001] [Citation(s) in RCA: 29] [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
We have developed a novel, high-throughput scintillation proximity assay to measure the membrane-associated steps (stages 2 and 3) of peptidoglycan synthesis in Escherichia coli. At least five enzymes are involved in these two stages, all of which are thought to be essential for the survival of the cell. The individual enzymes are difficult to assay since the substrates are lipidic and difficult to isolate in large quantities and analysis is done by paper chromatography. We have assayed all five enzymes in a single mixture by monitoring synthesis of cross-linked peptidoglycan, which is the final product of the pathway. E. coli membranes are incubated with the two sugar precursors, UDP-N-acetyl muramylpentapeptide and UDP-[(3)H]-N-acetylglucosamine. The radiolabel is incorporated into peptidoglycan, which is captured using wheat germ agglutinin-coated scintillation proximity assay beads. The assay monitors the activity of the translocase (MraY), the transferase (MurG), the lipid pyrophosphorylase, and the transglycosylase and transpeptidase activities of the penicillin-binding proteins. Vancomyin, tunicamycin, nisin, moenomycin, bacitracin, and penicillin inhibit the assay, and these inhibitors have been used to validate the assay. The search for new antimicrobial agents that act via the late stages of peptidoglycan biosynthesis can now be performed in high throughput in a microtiter plate.
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Affiliation(s)
- B Chandrakala
- AstraZeneca India Pvt. Ltd., Bangalore 560 003, India
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27
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Silva DJ, Bowe CL, Branstrom AA, Baizman ER, Sofia MJ. Synthesis and biological evaluation of analogues of bacterial lipid I. Bioorg Med Chem Lett 2000; 10:2811-3. [PMID: 11133098 DOI: 10.1016/s0960-894x(00)00583-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bacterial Lipid I analogues containing different anomeric groups at the muramic acid moiety were synthesized and screened in MurG enzyme assays run in the presence and absence of cell wall membranes. The results obtained in this study help elucidate the role of the lipid diphosphate in the recognition of Lipid I by MurG.
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Affiliation(s)
- D J Silva
- Department of Chemistry, Incara Research Laboratories, Cranbury, NJ 08536, USA.
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28
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Baizman ER, Branstrom AA, Longley CB, Allanson N, Sofia MJ, Gange D, Goldman RC. Antibacterial activity of synthetic analogues based on the disaccharide structure of moenomycin, an inhibitor of bacterial transglycosylase. MICROBIOLOGY (READING, ENGLAND) 2000; 146 Pt 12:3129-3140. [PMID: 11101671 DOI: 10.1099/00221287-146-12-3129] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Moenomycin is a natural product glycolipid that inhibits the growth of a broad spectrum of Gram-positive bacteria. In Escherichia coli, moenomycin inhibits peptidoglycan synthesis at the transglycosylation stage, causes accumulation of cell-wall intermediates, and leads to lysis and cell death. However, unlike Esc. coli, where 5-6 log units of killing are observed, 0-2 log units of killing occurred when Gram-positive bacteria were treated with similar multiples of the MIC. In addition, bulk peptidoglycan synthesis in intact Gram-positive cells was resistant to the effects of moenomycin. In contrast, synthetic disaccharides based on the moenomycin disaccharide core structure were identified that were bactericidal to Gram-positive bacteria, inhibited cell-wall synthesis in intact cells, and were active on both sensitive and vancomycin-resistant enterococci. These disaccharide analogues do not inhibit the formation of N:-acetylglucosamine-ss-1, 4-MurNAc-pentapeptide-pyrophosphoryl-undecaprenol (lipid II), but do inhibit the polymerization of lipid II into peptidoglycan in Esc. coli. In addition, cell growth was required for bactericidal activity. The data indicate that synthetic disaccharide analogues of moenomycin inhibit cell-wall synthesis at the transglycosylation stage, and that their activity on Gram-positive bacteria differs from moenomycin due to differential targeting of the transglycosylation process. Inhibition of the transglycosylation process represents a promising approach to the design of new antibacterial agents active on drug-resistant bacteria.
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Affiliation(s)
- Eugene R Baizman
- Advanced Medicine East Inc., 8 Clarke Drive, Cranbury, NJ 08512, USA1
| | | | | | - Nigel Allanson
- Advanced Medicine East Inc., 8 Clarke Drive, Cranbury, NJ 08512, USA1
| | - Michael J Sofia
- Advanced Medicine East Inc., 8 Clarke Drive, Cranbury, NJ 08512, USA1
| | - David Gange
- Advanced Medicine East Inc., 8 Clarke Drive, Cranbury, NJ 08512, USA1
| | - Robert C Goldman
- Advanced Medicine East Inc., 8 Clarke Drive, Cranbury, NJ 08512, USA1
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29
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Branstrom AA, Midha S, Goldman RC. In situ assay for identifying inhibitors of bacterial transglycosylase. FEMS Microbiol Lett 2000; 191:187-90. [PMID: 11024262 DOI: 10.1111/j.1574-6968.2000.tb09338.x] [Citation(s) in RCA: 21] [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
An in situ transglycosylase assay has been developed using endogenously synthesized lipid II. The assay involves the preferential synthesis and accumulation of lipid II in a reaction mixture containing the cell wall membrane material isolated from Escherichia coli, exogenously supplied UDP-MurNAc-pentapeptide, and radiolabeled UDP-GlcNAc. In the presence of Triton X-100, the radiolabeled product formed is almost exclusively lipid II, while the subsequent formation of peptidoglycan is inhibited. Removal of the detergent resulted in the synthesis of peptidoglycan (25% incorporation of radiolabeled material) from the accumulated lipid II. This reaction was inhibited by moenomycin, a known transglycosylase inhibitor. In addition, tunicamycin, which affects an earlier step of the pathway by inhibiting MraY, had no effect on the formation of peptidoglycan in this assay, as expected. Similarly, ampicillin and bacitracin did not inhibit the formation of peptidoglycan under the conditions established.
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Affiliation(s)
- A A Branstrom
- Advanced Medicine, Inc., 8 Clarke Drive, 08512, Cranbury, NJ, USA.
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