<prompt> All of the following statements about penicillin-binding proteins are true EXCEPT :Present on cell surfaceMutation in PBPs gives rise to resistanceThese are target site of vancomycinThese are targeted by imipenem  <response>: Beta-lactam antibiotics act by inhibiting the cross-linking of peptidoglycan chains in the bacterial cell wall. This action is carried out by transpeptidase enzyme. Transpeptidases and similar enzymes involved in cross-linking are called penicillin-binding proteins PBPs. All beta-lactam antibiotics bind to PBPs and inhibit cell wall synthesis. The drugs in p-lactam category are:PenicillinCephalosporinsCarbapenems e.g imipenemMonobactam e.g. aztreonamMutation in PBPs is an important cause of methicillin resistance in Staphylococcus aureus.Vancomycin does not bind to PBPs but acts by inhibiting transglycosylase. 