The cellular targets of penicillins are the so called penicillin-binding proteins (PBPs). Alterations in these enzymes that reduce their affinity for penicillins have been recognized as the major penicillin-resistance mechanism operating in S. pneumoniae. The normal function of PBPs is to synthesize the pneumococcal cell wall (the peptidoglycan sacculus).
Although the reactions catalyzed by the pneumococcal PBPs are well known, there are several aspects related to PBPs which are poorly understood. We therefore study:
- the specific role of each PBP in synthesizing and shaping the peptidoglycan sacculus
- regulation of PBP activity
- interaction between PBPs and other proteins
- sub-cellular localization of PBPs and the activities of low-affinity PBPs.