[Characterization of femA gene product by penicillin-binding protein assay].

To characterize the femA gene product by penicillin-binding protein (PBP) assay, cloned femA sequence was introduced into methicillin-sensitive femA mutant Staphylococcus aureus BB308 and into Escherichia coli JM109. Overproduced femA gene product was detected in the membrane fraction of the S. aureus and E. coli transformants by SDS-PAGE and Coomassie-blue staining, but no penicillin-binding activity was observed in the femA gene product. Both BB308 and its transformant produced PBP 2' and other PBPs, as much as clinically isolated methicillin-resistant S. aureus strains. The degree of restoration of methicillin resistance varied depending on the introduced femA sequences derived from six different S. aureus strains. A hypothetical mechanism of femA to affect beta-lactam resistance in S. aureus is discussed.