Staphylococcus aureus and Micrococcus luteus peptidoglycan transglycosylases that are not penicillin-binding proteins

Abstract

Major peptidoglycan transglycosylase activities, which synthesize uncross-linked peptidoglycan from lipid-linked precursors, were solubilized from the membranes of S. aureus and M. luteus and were partially purified. The transglycosylase activities were separated from pencillin-binding proteins by solubilization and by purification steps. Thus, these activities were not activities of the penicillin-binding proteins, which are the presumptive peptidoglycan transpeptidases in these gram-positive cocci. Unlike Escherichia coli, in which the network structure of peptidoglycan is synthesized by multiple 2-headed pencillin-binding proteins with both transpeptidase and transglycosylase activities, these gram-positive cocci have cell wall peptidoglycan which seems to be synthesized by penicillin-binding protein transpeptidases and a separate transglycosylase.