IMPORTANCE OF THE E-46-D-160 POLYPEPTIDE SEGMENT OF THE NON-PENICILLIN-BINDING MODULE FOR THE FOLDING OF THE LOW-AFFINITY, MULTIMODULAR CLASS-B PENICILLIN-BINDING PROTEIN-5 OF ENTEROCOCCUS-HIRAE

Compared with the other class B multimodular penicillin-binding protei ns (PBPs), the low-affinity PBP5 responsible for penicillin resistance in Enterococcus hirae R40, has an extended non-penicillin-binding mod ule because of the presence of an approximate to 110-amino-acid E-36-D -160 insert downstream from the membrane anchor. Expression of pbp5 ge nes lacking various parts of the insert-encoding region gives rise to proteins that are inert in terms of penicillin binding, showing that d uring folding of the PBP, the insert plays a role in the acquisition o f a correct penicillin-binding configuration by the G-364-Q-678 carbox y-terminal module.