CONSTRUCTION OF A MODIFIED PENICILLIN-BINDING PROTEIN 2A FROM METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS AND PURIFICATION BY IMMOBILIZED METAL AFFINITY-CHROMATOGRAPHY

The mecA-27r gene, which encodes PBP2a-27r, was modified by site-speci fic mutagenesis, resulting in replacement of the N-terminal membrane a nchor with a short chelating peptide (CP-PBP2a-27r). CP-CBP2a-27r reta ined the same binding affinity for p-lactam antibiotics as the wild-ty pe enzyme. Approximately 95% pure CP-PBP2a-27r was recovered in a sing le step by use of chelating-peptide-immobilized metal ion affinity chr omatography.