The effect of MurM and a branched cell wall structure on penicillin resistance in <i>Streptococcus pneumoniae</i>.

ABSTRACT: The aminoacyltransferase MurM is an important penicillin resistance determinant in Streptococcus pneumoniae. This enzyme attaches a serine or alanine to the side chain of lysine, the third residue of the pentapeptide of lipid II, resulting in branched muropeptides that can be crosslinked to stem peptides in peptidoglycan by penicillin binding proteins (PBPs). Deletion of murM results in only linear muropeptides, and more importantly, a significant reduction in resistance. Highly penicillin-resistant pneumococci express low-affinity PBPs, an altered MurM protein, and possess a highly branched cell wall. It has therefore been hypothesized that MurM, and thus branched muropeptides, are essential for resistance because they are better substrates for low-affinity PBPs. In this stu

SUBMITTER: Gjennestad RS 

PROVIDER: S-EPMC12632259 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature