Chemical composition and turnover of peptidoglycan in Neisseria gonorrhoeae

Abstract

The peptidoglycan of all four colonial types of a number of strains of Neisseria gonorrhoeae constituted 1 to 2% of the dry weight of the cell. The chemical composition of cell types examined was similar with molar ratios of 1:1:2:1:1 for muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid, respectively. Ninety-six percent of the mass of the peptidoglycan was composed of these compounds. A lipoprotein analogous to that observed in Escherichia coli was not detected. The chain length of the glycan varied from 80 to 110 disaccharide units. The peptide contained equimolar amounts of D- and L-alanine. The rate of turnover of peptidoglycan in strain RD5 was 50% per generation. Turnover proceeded without a lag and followed first-order kinetics.

A novel peptidoglycan‐linked lipoprotein (ComL) that functions in natural transformation competence of Neisseria gonorrhoeae

“…The association of palmitoylated ComL with the peptidoglycan of both E. coli and N. gonorrhoeae is consistent with earlier analyses indicating the structural identity of the gonococcal peptidoglycan layer and the E. coli murein sacculus (Hebeler and Young, 1976). The interaction of ComL and the peptidoglycan is probably by covalent linkage rather than by strong hydrophobic forces since ComL was not released from isolated murein by SDS, urea or formamide treatment.…”

“…It was also possible to locate ComL in the murein sacculus of N. gonorrhoeae (Fig. 5), which is reportedly identical to that of E. coli (Hebeler and Young, 1976). Mutant N457 completely lacks the labelled ComL, as does E. coli containing pDF84-T17.…”

“…Whether the lipid moiety of ComL resides in the inner or the outer membrane remains to be investigated. Several efforts were made to identify the gonococcal BLP homologue without success, leading to the conclusion that none exists (Hebeler and Young, 1976). Our attempts to complement the pleiotropic phenotype of E. coli lpp mutants with ComL failed because of lethal effects of ComL.…”

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

“…Purified peptidoglycan from N. gonorrhoeae contained glucosamine, muramic acid, alanine, glutamic acid and meso-diaminopimelic acid in the molar ratios of 1 : 1 : 2 : 1 : 1 as reported [1 ]. The O-acetyl content of a number of samples prepared by a method including boiling in 4% SDS at pH 5.1 for 1 h was equivalent to a molar proportion of 0.4 to 0.5 relative to diaminopimelic acid.…”

“…gonorrhoeae is exten-261 sively O-acetylated, as described earlier for N. pertiara [6]. It seems likely that the total lysozyme susceptibility observed earlier [1,2] may have been due to a preparative procedure involving long periods of heating in SDS. If the pH value had been greater than 7, then considerable losses of O-acetyl groups would have occurred.…”