Etude de la formation de l'acide N-glycolylmuramique du peptidoglycane de Nocardia asteroides

Gateau, Odile; C, Bordet; Michel, Georges

doi:10.1016/0304-4165(76)90305-6

Cited by 14 publications

(6 citation statements)

References 17 publications

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“…In one case, a modification of the muramic acid residue in the nucleotide precursor was described. 332 As reported here and in previous reviews, 1,6,10 variations in the specificity of the Mur synthetases are mainly responsible for the variations observed in the amino acids of the peptide subunit. However, growth in the presence of glycine, 158 -serine, 181 Although certain modifications involve the UDP-MurNAcpentapeptide, 333,334 most of them presumably occur at the level of the lipid intermediates as established in some cases.…”

Section: Structural Variations In the Monomer Unitsupporting

confidence: 59%

Recent advances in the formation of the bacterial peptidoglycan monomer unit (1985 to 2000)

2001

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Section: Structural Variations In the Monomer Unitsupporting

confidence: 59%

Recent advances in the formation of the bacterial peptidoglycan monomer unit (1985 to 2000)

2001

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“…4). Such activity has been found in M. phlei and in Nocardia asteroides (Gateau et al, 1976;Essers & Schoop, 1978). Recently, the namH gene encoding a UDP-MurNAc-pentapeptide monooxygenase was identified in M. smegmatis (Raymond et al, 2005).…”

Section: N-glycolylation Of Muramic Acidmentioning

confidence: 92%

Structural variation in the glycan strands of bacterial peptidoglycan

2008

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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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“…MurNAc hydroxylase activity was first described in the actinobacterial species N. asteroides nearly 30 years ago using an assay that monitored the NADPH-dependent conversion of radiolabeled UDP-MurNAc to UDP-MurNGlyc (15). The substrate and product were detected using paper chromatography with comparison to chemically synthesized standards.…”

Section: Development Of the Udp-murnac Hydroxylase Assay-udp-mentioning

confidence: 99%

“…Previous work with Mycobacterium phlei established that the production of N-glycolylmuramic acid in mycobacteria likely occurs by the action of an atmospheric oxygen-dependent hydroxylase that converts UDP-MurNAc to UDP-MurNGlyc (14). In addition, a soluble activity present in Nocardia asteroides capable of converting UDP-MurNAc to UDP-MurNGlyc in an NADPH-dependent fashion was demonstrated almost 30 years ago (15), but since then no UDP-MurNAc hydroxylase has been purified and no gene identified from any bacterial species.…”

mentioning

confidence: 99%

Identification of the namH Gene, Encoding the Hydroxylase Responsible for the N-Glycolylation of the Mycobacterial Peptidoglycan

Raymond

Mahapatra

Crick

et al. 2005

Journal of Biological Chemistry

162

158

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The peptidoglycan of most bacteria consists of a repeating disaccharide unit of ␤-1,4-linked N-acetylmuramic acid and N-acetylglucosamine. However, the muramic acid moieties of the mycobacterial peptidoglycan are N-glycolylated, not N-acetylated. This is a rare modification seen only in the peptidoglycan of mycobacteria and five other closely related genera of bacteria. The N-glycolylation of sialic acids is a unique carbohydrate modification that has been studied extensively in eukaryotes. However, the significance of the N-glycolylation of bacterial peptidoglycan is unknown. The goal of this project was to identify the gene encoding the hydroxylase responsible for the N-glycolylation of the mycobacterial peptidoglycan. We developed a novel assay for the mycobacterial UDP-N-acetylmuramic acid hydroxylation reaction and demonstrated that Mycobacterium smegmatis has an enzyme activity that can convert UDP-N-acetylmuramic acid to UDP-N-glycolylmuramic acid. We identified the gene namH encoding the mycobacterial UDP-N-acetylmuramic acid hydroxylase by computer data base searching and motif comparisons with the eukaryotic enzymes responsible for the N-glycolyation of sialic acids. The namH gene is not essential for in vitro growth as we were successful in deleting the gene in M. smegmatis. The M. smegmatis mutant is devoid of UDP-N-acetylmuramic acid hydroxylase activity and synthesizes only N-acetylated muropeptide precursors. Furthermore, the mutant exhibits increased susceptibility to ␤-lactam antibiotics and lysozyme. Our studies suggest that the N-glycolylation of mycobacterial peptidoglycan may play a role in lysozyme resistance or may contribute to the structural stability of the cell wall architecture.

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Etude de la formation de l'acide N-glycolylmuramique du peptidoglycane de Nocardia asteroides

Cited by 14 publications

References 17 publications

Recent advances in the formation of the bacterial peptidoglycan monomer unit (1985 to 2000)

Recent advances in the formation of the bacterial peptidoglycan monomer unit (1985 to 2000)

Structural variation in the glycan strands of bacterial peptidoglycan

Identification of the namH Gene, Encoding the Hydroxylase Responsible for the N-Glycolylation of the Mycobacterial Peptidoglycan

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