All of the following statements about penicillin binding proteins (PBP) are true, except -
Ans. is 'a' i.e., PBP'S are localized on the outer face of cell wall Penicillin binding proteins (PBPs) o S. aureus strains have four normal penicillin binding proteins (PBPs) anchored on the cytoplasmic membrane. o PBPs are essential for cell wall synthesis by paicipating in the crosslinking of the peptidoglycan of bacterial cell wall. o PBPs act as transpeptidases and carboxypeptidases. o These PBPs have activity similar to that serine protease and high affinity for beta-lactam agent. o When bea-lactam antibiotic binds to PBPs, the PBPs are not available to function in the assembly of cell wall causing bacterial death. o PBP2a on the other hand, is not pa of the intrinsic set of PBPs of s.aureus but is an inducible acquired protein (extra PBP) that is produced only by methicillin resistant s.aureus (MRSA). o PBP2a has very low affinity for beta-lactam antibiotic --> beta-lactam antibiotics cannot bind to its receptor (PBP) and the organism (MRSA) is resistant to all available beta-lactam antibiotics. o PBP2a is encoded by the mec A gene, which is not present in methicillin susceptible s.aureus (Present only in MRSA).
PBP'S are localized on the outer face of cell wall
PBP's are essential for cell wall synthesis
PBP's act as carboxypeptidases and traspeptidases
Alteration in PBP's is the primary bases of resistance in MRSA