CELL WALL POLYMERS OF BACILLUS SPHAERICUS 9602 .I. STRUCTURE OF VEGETATIVE CELL WALL PEPTIDOGLYCAN

Peptidoglycan constitutes 23% of the cell walls of Bacillus sphaericus strain 9602. Its glycan consists of alternating residues of A-acetylmuramic acid and V-acetvlglucosamine, probably linked β-1,4 as in all known bacterial cell wall peptidoglycans. Every muramic acid residue of this glycan is substituted by Nα-(L-alanyl-D-isoglutamyl)-Nϵ-(β-Disoasparaginyl)-L-lysine tetrapeptides, 55 % of which are crosslinked between L-lysine and D-isoasparagine by D-alanine residues to give oligomers of this peptide of random chain length. The subunits of this peptidoglycan thus differ from those of Streptococcus faecium and Lactobacillus casei RG94 only in lacking C-terminal D-alanine residues and amidation of their glutamic α-carboxyl groups. Their pattern of peptide crosslinking is very similar to that of L. casei. Much of the rest of the cell wall consists of protein which is trypsin and pronase sensitive. The walls also contain at least one other polymer, which contains glucosamine, and which is covalently bound to the peptidoglycan. © 1969, American Chemical Society. All rights reserved.