femA, which encodes a factor essential for expression of methicillin resistance, affects glycine content of peptidoglycan in methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains.

摘要: femA is a chromosomally encoded factor, occurring naturally in Staphylococcus aureus, which essential for the expression of high-level methicillin resistance this organism. The production low-affinity penicillin-binding protein, PBP2a or PBP2', intimately involved with S. not influenced by femA. To elucidate possible physiological function 48-kDa protein femA, several related methicillin-resistant, methicillin-susceptible, and Tn551 insertionally inactivated mutants were analyzed changes cell wall structure metabolism. Independent presence mec, determinant, all had reduced peptidoglycan (PG) glycine content (up to 60% molar ratio glycine/glutamic acid) compared that femA+ parent strains. Additional effects inactivation subsequent decrease PG-associated (i) digestion PG recombinant lysostaphin, (ii) unaltered Chalaropsis B-muramidase, (iii) turnover, (iv) whole-cell autolysis, (v) increased sensitivity towards beta-lactam antibiotics. Also, femA::Tn551 methicillin-susceptible strain was restored concomitantly level almost equal its methicillin-resistant introduction plasmid pBBB31, encoding