The peptidoglycan of Neisseria gonorrhoeae: O-acetyl groups and lysozyme sensitivity

Blundell, Jennifer

doi:10.1016/0378-1097(80)90028-2

Cited by 28 publications

(42 citation statements)

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“…These data are thus analogous to those obtained with both N. gonorrhoeae (6,35,36,41) and P. mirabilis (9,11,16), in which resistance to HEWL was shown to be directly proportional to the levels of O acetylation. More importantly, however, the data help explain very early observations regarding large variations in the lytic response of enterococcal cells to HEWL (7,42), which was later found to be dependent on the strain used and the growth phase from which the cells were obtained (17,31).…”

Section: Resultsmentioning

confidence: 52%

“…For each species and strain examined, the extent of peptidoglycan O acetylation is not stoichiometric but instead ranges typically between 20% and 70% relative to the muramic acid content. Nonetheless, this modification has been shown to inhibit the lytic action of the muramidases (lysozymes) associated with the innate immune system in a concentration-dependent manner (6,16,35,36,41). The O acetylation of peptidoglycan has also been demonstrated to inhibit the action of the lytic transglycosylases (5), which are ubiquitous bacterial enzymes associated with peptidoglycan metabolism (both biosynthesis and turnover) (4).…”

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confidence: 99%

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Peptidoglycan O Acetylation and Autolysin Profile ofEnterococcus faecalisin the Viable but Nonculturable State

et al. 2006

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The O acetylation of peptidoglycan occurs specifically at the C-6 hydroxyl group of muramoyl residues. Using a combination of high-performance liquid chromatography-based organic acid analysis and carbohydrate analysis by high-pH anion-exchange chromatography, we determined that strains of Entercoccus durans, E. faecalis, E. faecium, and E. hirae produce O-acetylated peptidoglycan. The levels of O acetylation ranged from 19% to 72% relative to the muramic acid content, and they were found to vary with the growth phase of the culture. Increases of 10 to 40% in O acetylation were observed with cultures entering the stationary phase. Cells of E. faecalis in the viable but nonculturable (VBNC) state had the highest levels of peptidoglycan O acetylation. The presence of this modification to peptidoglycan was shown to inhibit the action of hen egg white lysozyme in a concentration-dependent manner. Zymography using sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels containing either O-acetylated or chemically de-O-acetylated peptidoglycan was used to monitor the production of specific autolysins in E. faecalis. Differences in the expression of specific autolysins were observed with the age of the culture, and VBNC E. faecalis produced the highest levels of these enzymes. This technique also permitted classification of the enterococcal autolysins into enzymes that preferentially hydrolyze either O-acetylated or non-O-acetylated peptidoglycan and enzymes that show no apparent preference for either substrate type.The gram-positive, gut commensal bacterium Enterococcus faecalis is the causative agent of 90% of all enterococcal infections, which include endocarditis, bacteremia, and urinary tract infections. Of these, urinary tract infections are the most common, and the majority of them are acquired nosocomially. E. faecalis infections pose problems for the clinician because of their resistance to multiple antibiotics, sometimes including vancomycin, the drug of last resort for many gram-positive infections (recently reviewed in references 14, 19, and 32). To exacerbate this situation, this bacterium has been shown to persist in a mouse model for extended periods of time in the kidney (26). This persistence is thought to result from the cell's ability to enter the viable but nonculturable (VBNC) state, a feature first described for E. faecalis by Lleo et al. (30). VBNC E. faecalis, like other VBNC pathogenic bacteria, appears to retain its pathogenicity genes and is able to resume active growth upon restoration of the optimal environmental conditions (reference 30 and references therein). While in this state, E. faecalis cells have an irregular morphology, and there are concomitant alterations in the molecular architecture of the peptidoglycan sacculus (39). However, the changes observed in the peptidoglycan composition do not readily account for the persistence associated with the VBNC enterococci. One possible explanation for the apparent resilience of VBNC E. faecalis could involve a modification to the pep...

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Section: Resultsmentioning

confidence: 52%

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confidence: 99%

Peptidoglycan O Acetylation and Autolysin Profile ofEnterococcus faecalisin the Viable but Nonculturable State

et al. 2006

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“…However, mAb 3D6 reacted preferentially with Brucella PG. This could be due to structural differences between E. coli and Brucella PG, possibly due to 0-acetylation (Blundell et al, 1980;Dougherty, 1983;Gmeiner & Kroll, 1981;Lear & Perkins, 1983;Rosenthal et al, 1982Rosenthal et al, , 1983Swim et al, 1983) or the degree of peptide cross-linking (Amano & Williams, 1983;Lear & Perkins, 1983), which confer a greater resistance of PG to lysozyme hydrolysis. The large differences between immunoblots of untreated and lysozyme-treated sonicated cell extracts revealed by mAbs specific for the major OMPs suggest that large amounts of these proteins are tightly associated, presumably covalently, to the PG.…”

Section: Discussionmentioning

confidence: 99%

Demonstration of peptidoglycan-associated Brucella outer-membrane proteins by use of monoclonal antibodies

Cloeckaert

Zygmunt

Wergifosse

et al. 1992

Journal of General Microbiology

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A monoclonal antibody (3D6) was produced which reacted only with Brucellu sonicated cell extracts that had been lysozyme-treated after sonication. The monoclonal antibody (mAb) reacted with the three major outermembrane proteins (OMPs) of B. melitensis B115 in Western blots. A large number of reactive bands ranging from 12 to 43 kDa were present in lysozyme-treated Escherichia coli and Yersiniu enterocolitica sonicated cell extracts. In a latex agglutination inhibition immunoassay, mAb 3D6 showed better reactivity with purified peptidoglycan (PG) of B. melitensis B115 than with that of Escherichia coli. This mAb was also used in immunogold electron microscopy with whole Brucellu cells and sections. No binding was observed on whole cells and immunogold labelling in sections was observed close to the outer membrane, in the periplasmic space and in the cytoplasm.These findings indicate that mAb 3D6 is specific for PG subunits. Immunoblot analysis of B. melitensis B115 rough sonicated cell extracts after SDS-PAGE, with or without lysozyme treatment, was performed using mAbs specific for Brucella OMPs of molecular masses of 10,16.5,19,25-27,31-34,36-38 and 89 kDa, for PG and for rough lipopolysaccharide (R-LPS) and smooth lipopolysaccharide (S-LPS). mAbs specific for the 25-27, 31-34 and 36-38 kDa OMPs reacted with three to six bands. All of them except the band of lowest molecular mass reacted with the PG-specific mAb and not with R-LPS-and S-LPS-specific mAbs. Therefore we propose that variation in the apparent molecular mass of the major OMPs (25-27,31-34, and 36-38 kDa) is due to varying numbers of PG subunit residues rather than attached R-LPS or S-LPS molecules. Our results suggest a very strong, possibly covalent, interaction of the major OMPs (2527, 31-34 and 36-38kDa) with PG. There is no evidence of association of the minor OMPs (10,16.5,19 and 89 kDa) with PG, since mAbs specific for these proteins reacted with single bands that were not apparent when reacted with the anti-PG mAb. Furthermore, lysozyme treatment did not affect the electrophoretic mobility of these proteins.

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“…The O-acetylation of PG has been demonstrated to inhibit the activity of lysozyme in a concentration-dependent manner (5)(6)(7)(8)(9), including that of the innate immune system. As a result, large fragments of undegraded PG persist to cause a number of pathobiological effects, including rheumatoid arthritis (reviewed in Refs.…”

Section: Discussionmentioning

confidence: 99%

O-Acetylation of Peptidoglycan in Gram-negative Bacteria

Moynihan

Clarke

2010

Journal of Biological Chemistry

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The ape2 gene encoding a hypothetical O-acetylpeptidoglycan esterase was amplified from genomic DNA of Neisseria gonorrhoeae FA1090 and cloned to encode either the full-length protein or a truncated version lacking its hypothetical signal sequence. Expression trials revealed that production of the fulllength version possessing either an N-terminal or C-terminal His 6 tag was toxic to Escherichia coli transformants and that the host rapidly degraded the small amount of protein that was produced. An N-terminally truncated protein could be produced in sufficient yields for purification only if it possessed an N-terminal His 6 tag. This form of the protein was isolated and purified to apparent homogeneity, and its enzymatic properties were characterized. Whereas the protein could bind to insoluble peptidoglycan, it did not function as an esterase. Phenotypic characterization of E. coli transformants producing various forms of the protein revealed that it functions instead to O-acetylate peptidoglycan within the periplasm, and it was thus renamed peptidoglycan O-acetyltransferase B. This activity was found to be dependent upon a second protein, which functions to translocate acetate from the cytoplasm to the periplasm, demonstrating that the O-acetylation of peptidoglycan in N. gonorrhoeae, and other Gram-negative bacteria, requires a two component system. The bacterial cell wall heteropolymer peptidoglycan (PG)2 is comprised of alternating N-acetylglucosaminyl-␤-1,4-Nacetylmuramoyl residues with attached stem peptides. The existence of the peptides permits interpeptide cross-linking between neighboring strands of PG to provide a continuous three-dimensional macromolecule, the PG sacculus. This sacculus completely surrounds the bacterial cell over its cytoplasmic membrane to withstand the internal turgor pressure of the cell and thereby providing structural rigidity and shape to the cells. Given the essential role in the vitality of bacterial cells, the PG sacculus is the target of lytic enzymes such as lysozyme (muramidases), which are produced and released by eukaryotic hosts as the first line of defense against invasion. As found with the xylans of plant cell walls (reviewed in Ref.

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The peptidoglycan of Neisseria gonorrhoeae: O-acetyl groups and lysozyme sensitivity

Cited by 28 publications

References 4 publications

Peptidoglycan O Acetylation and Autolysin Profile ofEnterococcus faecalisin the Viable but Nonculturable State

Peptidoglycan O Acetylation and Autolysin Profile ofEnterococcus faecalisin the Viable but Nonculturable State

Demonstration of peptidoglycan-associated Brucella outer-membrane proteins by use of monoclonal antibodies

O-Acetylation of Peptidoglycan in Gram-negative Bacteria

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