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Abstract
Mycobacteria are responsible for several human and animal diseases. NOD2 is a pattern recognition receptor that has an important role in mycobacterial recognition. However, the mechanisms by which mutations in NOD2 alter the course of mycobacterial infection remain unclear. Herein, we aimed to review the totality of studies directly addressing the relationship between NOD2 and mycobacteria as a foundation for moving the field forward. NOD2 was linked to mycobacterial infection at 3 levels: (1) genetic, through association with mycobacterial diseases of humans; (2) chemical, through the distinct NOD2 ligand in the mycobacterial cell wall; and (3) immunologic, through heightened NOD2 signaling caused by the unique modification of the NOD2 ligand. The immune response to mycobacteria is shaped by NOD2 signaling, responsible for NF-κB and MAPK activation, and the production of various immune effectors like cytokines and nitric oxide, with some evidence linking this to bacteriologic control. Absence of NOD2 during mycobacterial infection of mice can be detrimental, but the mechanism remains unknown. Conversely, the success of immunization with mycobacteria has been linked to NOD2 signaling and NOD2 has been targeted as an avenue of immunotherapy for diseases even beyond mycobacteria. The mycobacteria-NOD2 interaction remains an important area of study, which may shed light on immune mechanisms in disease.
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Affiliation(s)
- Jean-Yves Dubé
- Department of Microbiology and Immunology, McGill University, Montréal, Canada
| | - Marcel A Behr
- Department of Medicine, McGill University Health Centre, Montréal, Canada
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Halouska S, Fenton RJ, Zinniel DK, Marshall DD, Barletta RG, Powers R. Metabolomics analysis identifies d-Alanine-d-Alanine ligase as the primary lethal target of d-Cycloserine in mycobacteria. J Proteome Res 2013; 13:1065-76. [PMID: 24303782 DOI: 10.1021/pr4010579] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
d-Cycloserine is an effective second line antibiotic used as a last resort to treat multi (MDR)- and extensively (XDR) drug resistant strains of Mycobacterium tuberculosis . d-Cycloserine interferes with the formation of peptidoglycan biosynthesis by competitive inhibition of alanine racemase (Alr) and d-alanine-d-alanine ligase (Ddl). Although the two enzymes are known to be inhibited, the in vivo lethal target is still unknown. Our NMR metabolomics work has revealed that Ddl is the primary target of DCS, as cell growth is inhibited when the production of d-alanyl-d-alanine is halted. It is shown that inhibition of Alr may contribute indirectly by lowering the levels of d-alanine, thus allowing DCS to outcompete d-alanine for Ddl binding. The NMR data also supports the possibility of a transamination reaction to produce d-alanine from pyruvate and glutamate, thereby bypassing Alr inhibition. Furthermore, the inhibition of peptidoglycan synthesis results in a cascading effect on cellular metabolism as there is a shift toward the catabolic routes to compensate for accumulation of peptidoglycan precursors.
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Affiliation(s)
- Steven Halouska
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0304, United States
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Bacterial growth and cell division: a mycobacterial perspective. Microbiol Mol Biol Rev 2008; 72:126-56, table of contents. [PMID: 18322037 DOI: 10.1128/mmbr.00028-07] [Citation(s) in RCA: 271] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Mycobacterium is best known for its two major pathogenic species, M. tuberculosis and M. leprae, the causative agents of two of the world's oldest diseases, tuberculosis and leprosy, respectively. M. tuberculosis kills approximately two million people each year and is thought to latently infect one-third of the world's population. One of the most remarkable features of the nonsporulating M. tuberculosis is its ability to remain dormant within an individual for decades before reactivating into active tuberculosis. Thus, control of cell division is a critical part of the disease. The mycobacterial cell wall has unique characteristics and is impermeable to a number of compounds, a feature in part responsible for inherent resistance to numerous drugs. The complexity of the cell wall represents a challenge to the organism, requiring specialized mechanisms to allow cell division to occur. Besides these mycobacterial specializations, all bacteria face some common challenges when they divide. First, they must maintain their normal architecture during and after cell division. In the case of mycobacteria, that means synthesizing the many layers of complex cell wall and maintaining their rod shape. Second, they need to coordinate synthesis and breakdown of cell wall components to maintain integrity throughout division. Finally, they need to regulate cell division in response to environmental stimuli. Here we discuss these challenges and the mechanisms that mycobacteria employ to meet them. Because these organisms are difficult to study, in many cases we extrapolate from information known for gram-negative bacteria or more closely related GC-rich gram-positive organisms.
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Abstract
The normal, unmodified glycan strands of bacterial peptidoglycan consist of alternating residues of beta-1,4-linked N-acetylmuramic acid and N-acetylglucosamine. In many species the glycan strands become modified after their insertion into the cell wall. This review describes the structure of secondary modifications and of attachment sites of surface polymers in the glycan strands of peptidoglycan. It also provides an overview of the occurrence of these modifications in various bacterial species. Recently, enzymes responsible for the N-deacetylation, N-glycolylation and O-acetylation of the glycan strands were identified. The presence of these modifications affects the hydrolysis of peptidoglycan and its enlargement during cell growth. Glycan strands are frequently deacetylated and/or O-acetylated in pathogenic species. These alterations affect the recognition of bacteria by host factors, and contribute to the resistance of bacteria to host defence factors such as lysozyme.
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Affiliation(s)
- Waldemar Vollmer
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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Mahapatra S, Yagi T, Belisle JT, Espinosa BJ, Hill PJ, McNeil MR, Brennan PJ, Crick DC. Mycobacterial lipid II is composed of a complex mixture of modified muramyl and peptide moieties linked to decaprenyl phosphate. J Bacteriol 2005; 187:2747-57. [PMID: 15805521 PMCID: PMC1070386 DOI: 10.1128/jb.187.8.2747-2757.2005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Structural analysis of compounds identified as lipid I and II from Mycobacterium smegmatis demonstrated that the lipid moiety is decaprenyl phosphate; thus, M. smegmatis is the first bacterium reported to utilize a prenyl phosphate other than undecaprenyl phosphate as the lipid carrier involved in peptidoglycan synthesis. In addition, mass spectrometry showed that the muropeptides from lipid I are predominantly N-acetylmuramyl-L-alanine-D-glutamate-meso-diaminopimelic acid-D-alanyl-D-alanine, whereas those isolated from lipid II form an unexpectedly complex mixture in which the muramyl residue and the pentapeptide are modified singly and in combination. The muramyl residue is present as N-acetylmuramic acid, N-glycolylmuramic acid, and muramic acid. The carboxylic functions of the peptide side-chains of lipid II showed three types of modification, with the dominant one being amidation. The preferred site for amidation is the free carboxyl group of the meso-diaminopimelic acid residue. Diamidated species were also observed. The carboxylic function of the terminal D-alanine of some molecules is methylated, as are all three carboxylic acid functions of other molecules. This study represents the first structural analysis of mycobacterial lipid I and II and the first report of extensive modifications of these molecules. The observation that lipid I was unmodified strongly suggests that the lipid II intermediates of M. smegmatis are substrates for a variety of enzymes that introduce modifications to the sugar and amino acid residues prior to the synthesis of peptidoglycan.
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Affiliation(s)
- Sebabrata Mahapatra
- Mycobacterial Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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Yabu K, Huempfner HR. Inhibition of growth of Mycobacterium smegmatis and of cell wall synthesis by D-serine. Antimicrob Agents Chemother 2005; 6:1-10. [PMID: 15828163 PMCID: PMC429039 DOI: 10.1128/aac.6.1.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
d-Serine inhibited the growth of Mycobacterium smegmatis and induced the morphological alteration of the bacilli. The growth inhibitory action of d-serine was partially reduced by an equimolecular concentration of d-alanine. The combination of glycine with d-alanine reversed the growth inhibition produced by d-serine more than did d-alanine alone. In cells cultured in the presence of d-serine, the amounts of alanine, diaminopimelic acid, and glycine inserted into the cell wall mucopeptide were reduced, and serine was increased. The intracellular accumulation of a precursor of cell wall mucopeptide was increased by d-serine, and this accumulation was reduced by d-alanine. d-Serine competed with glycine for incorporation into the cell wall mucopeptide. The incorporation of l-aspartic acid into diaminopimelic acid residues in the cell wall mucopeptide was markedly inhibited by d-serine. Three mutants resistant to d-serine were isolated by nitrosoguanidine treatment. In these mutants the effects of d-serine on the sites of cell wall mucopeptide synthesis were all reduced. Thus, d-serine inhibition of the growth is due to replacement of glycine residues of the cell wall mucopeptide with d-serine and inhibition of the cell wall synthesis by blocking the formation of d-alanine and diaminopimelic acid.
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Mahapatra S, Scherman H, Brennan PJ, Crick DC. N Glycolylation of the nucleotide precursors of peptidoglycan biosynthesis of Mycobacterium spp. is altered by drug treatment. J Bacteriol 2005; 187:2341-7. [PMID: 15774877 PMCID: PMC1065221 DOI: 10.1128/jb.187.7.2341-2347.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The peptidoglycan of Mycobacterium spp. reportedly has some unique features, including the occurrence of N-glycolylmuramic rather than N-acetylmuramic acid. However, very little is known of the actual biosynthesis of mycobacterial peptidoglycan, including the extent and origin of N glycolylation. In the present work, we have isolated and analyzed muramic acid residues located in peptidoglycan and UDP-linked precursors of peptidoglycan from Mycobacterium tuberculosis and Mycobacterium smegmatis. The muramic acid residues isolated from the mature peptidoglycan of both species were shown to be a mixture of the N-acetyl and N-glycolyl derivatives, not solely the N-glycolylated product as generally reported. The isolated UDP-linked N-acylmuramyl-pentapeptide precursor molecules also contain a mixture of N-acetyl and N-glycolyl muramyl residues in apparent contrast to previous observations in which the precursors isolated after treatment with d-cycloserine consisted entirely of N-glycolyl muropeptides. However, nucleotide-linked peptidoglycan precursors isolated from M. tuberculosis treated with d-cycloserine contained only N-glycolylmuramyl-tripeptide precursors, whereas those from similarly treated M. smegmatis consisted of a mixture of N-glycolylated and N-acetylated residues. The full pentapeptide intermediate, isolated following vancomycin treatment of M. smegmatis, consisted of the N-glycolyl derivative only, whereas the corresponding M. tuberculosis intermediate was a mixture of both the N-glycolyl and N-acetyl products. Thus, treatment with vancomycin and d-cylcoserine not only caused an accumulation of nucleotide-linked intermediate compounds but also altered their glycolylation status, possibly by altering the normal equilibrium maintained by de novo biosynthesis and peptidoglycan recycling.
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Affiliation(s)
- Sebabrata Mahapatra
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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Dover LG, Cerdeño-Tárraga AM, Pallen MJ, Parkhill J, Besra GS. Comparative cell wall core biosynthesis in the mycolated pathogens, Mycobacterium tuberculosis and Corynebacterium diphtheriae. FEMS Microbiol Rev 2004; 28:225-50. [PMID: 15109786 DOI: 10.1016/j.femsre.2003.10.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2003] [Revised: 09/23/2003] [Accepted: 10/04/2003] [Indexed: 11/17/2022] Open
Abstract
The recent determination of the complete genome sequence of Corynebacterium diphtheriae, the aetiological agent of diphtheria, has allowed a detailed comparison of its physiology with that of its closest sequenced pathogenic relative Mycobacterium tuberculosis. Of major importance to the pathogenicity and resilience of the latter is its particularly complex cell envelope. The corynebacteria share many of the features of this extraordinary structure although to a lesser level of complexity. The cell envelope of M. tuberculosis has provided the molecular targets for several of the major anti-tubercular drugs. Given a backdrop of emerging multi-drug resistant strains of the organism (MDR-TB) and its continuing global threat to human health, the search for novel anti-tubercular agents is of paramount importance. The unique structure of this cell wall and the importance of its integrity to the viability of the organism suggest that the search for novel drug targets within the array of enzymes responsible for its construction may prove fruitful. Although the application of modern bioinformatics techniques to the 'mining' of the M. tuberculosis genome has already increased our knowledge of the biosynthesis and assembly of the mycobacterial cell wall, several issues remain uncertain. Further analysis by comparison with its relatives may bring clarity and aid the early identification of novel cellular targets for new anti-tuberculosis drugs. In order to facilitate this aim, this review intends to illustrate the broad similarities and highlight the structural differences between the two bacterial envelopes and discuss the genetics of their biosynthesis.
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Affiliation(s)
- Lynn G Dover
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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Chopra I, Brennan P. Molecular action of anti-mycobacterial agents. TUBERCLE AND LUNG DISEASE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS AND LUNG DISEASE 1998; 78:89-98. [PMID: 9692177 DOI: 10.1016/s0962-8479(98)80001-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In terms of the paradigms for antibacterial action presented in the introduction, there is good evidence that broad spectrum agents exert their anti-mycobacterial activity by interaction with classical targets occurring in a wide range of organisms including the mycobacteria. This is supported either by direct evidence (e.g., inhibition by rifampicin of mycobacterial RNA polymerase), or indirectly by the characterization of drug-resistant mycobacteria where mutations conferring resistance have been mapped to target sites homologous to those found in other bacteria (fluoroquinolones, macrolides, rifampicin, streptomycin). On the other hand, although the mode of action of some of the agents with an anti-mycobacterial spectrum is not fully understood, it is evident that the restricted spectrum is likely to arise from the possession of unique targets, or specific pro-drug conversion systems, or to a combination of both mechanisms. In several cases the narrow spectrum of the agents can be attributed to inhibition of molecular targets involved in the biosynthesis of the mycobacterial cell envelope that contains many unique polymers. The recent re-emergence of tuberculosis as an important human pathogen has led to improved methods for exploring the structure, biochemistry and genetics of the mycobacteria. These technical advances can now be used to gain a better understanding of the molecular basis of drug action in mycobacteria.
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Affiliation(s)
- I Chopra
- Antimicrobial Research Centre, University of Leeds, UK
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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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Rastogi N, David HL. Mode of action of antituberculous drugs and mechanisms of drug resistance in Mycobacterium tuberculosis. Res Microbiol 1993; 144:133-43. [PMID: 8337471 DOI: 10.1016/0923-2508(93)90028-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- N Rastogi
- Unité de la Tuberculose et des Mycobactéries, Institut Pasteur, Paris
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Alterations in the outer wall architecture caused by the inhibition of mycoside C biosynthesis inMycobacterium avium. Curr Microbiol 1988. [DOI: 10.1007/bf01568787] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Essers L, Schoop HJ. Evidence for the incorporation of molecular oxygen, a pathway in biosynthesis of N-glycolylmuramic acid in Mycobacterium phlei. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 544:180-4. [PMID: 718994 DOI: 10.1016/0304-4165(78)90221-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The hypothesis that the biosynthesis of the glycolyl group of muramic acid in the peptidoglycan of Mycobacterium phlei is catalyzed by a N-acetyl hydroxylase is strongly supported by the experiments reported in this paper. 18O is incorporated into the N-substituent of muramic acid isolated from the peptidoglycan of M. phlei grown under pure oxygen enriched with the 18O isotope.
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Lederer E, Adam A, Ciorbaru R, Petit JF, Wietzerbin J. Cell walls of Mycobacteria and related organisms; chemistry and immunostimulant properties. Mol Cell Biochem 1975; 7:87-104. [PMID: 1095912 DOI: 10.1007/bf01792076] [Citation(s) in RCA: 132] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Takayama K, Schnoes HK, Semmler EJ. Characterization of the alkali-stable mannophospholipids of Mycobacterium smegmatis. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 316:212-21. [PMID: 4741910 DOI: 10.1016/0005-2760(73)90011-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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