H. Komatsuzawa et al., Cloning and characterization of a gene, pbpF, encoding a new penicillin-binding protein, PBP2B, in Staphylococcus aureus, ANTIM AG CH, 43(7), 1999, pp. 1578-1583
A previously unrecognized penicillin binding protein (PBP) gene, pbpF; was
identified in Staphylococcus aureus. This gene encodes a protein of 691 ami
no acid residues with an estimated molecular mass of 78 kDa. The molecular
mass is very close to that of S. aureus PBP2 (81 kDa), and the protein is t
entatively named PBP2B, PBP2B has three motifs, SSVK, SSN, and KTG, that ca
n be found in PBPs and beta-lactamases. Recombinant PBP2B (rPBP2B), which l
acks a putative signal peptide at the N terminus and has a histidine tag at
the C terminus, was expressed in Escherichia coli. The purified rPBP2B was
shown to have penicillin binding activity. A protein band was detected fro
m S. aureus membrane fraction by immunoblotting with anti-rPBP2B serum. Als
o, penicillin binding activity of the protein immunoprecipitated with anti-
rPBP2B serum was detected. These results suggest the presence of PBP2B in S
. aureus cell membrane that covalently binds penicillin. The internal regio
n of pbpF and PBP2B protein were found in all 12 S. aureus strains tested b
y PCR and immunoblotting.