Affinities of SM-7338 for penicillin-binding proteins and its release from these proteins in Staphylococcus aureus

Abstract

SM-7338, a carbapenem antibiotic, had high affinities for penicillin-binding proteins (PBPs) 1, 2, and 4 of Staphylococcus aureus but not for PBP 3 when a competition assay with [14C]benzylpenicillin was used. However, binding of [14C]SM-7338 was saturated for PBP 3 at a concentration of 1 microgram/ml. These results were due to the rapid release of SM-7338 from PBP 3-SM-7338 complexes with a half-life of 2 min.