The emergence of multi-drug-resistant strains of Staphylococcus epidermidis emphasizes the
need to develop new antibiotics. The unique and essential role of the peptide deformylase (PDF)
in catalysing the removal of the N-terminal formyl group from newly synthesized polypeptides in
eubacteria makes it an attractive antibacterial drug target. In the present study, both deformylase
homologues from S. epidermidis (SePDF-1 and SePDF-2) were cloned and expressed, and their
enzymic activities were characterized. Co2+-substituted SePDF-1 exhibited much higher enzymic
activity (kcat/Km 6.3104 M”1 s”1) than those of Ni2+- and Zn2+-substituted SePDF-1, and
SePDF-1 showed much weaker binding ability towards Ni2+ than towards Co2+ and Zn2+,
which is different from PDF in Staphylococcus aureus (SaPDF), although they share 80% aminoacid
sequence identity. The determined crystal structure of SePDF-1 was similar to that of
(SaPDF), except for differences in the metal-binding sites. The other deformylase homologue,
SePDF-2, was shown to have no peptide deformylase activity; the function of SePDF-2 needs to
be further investigated.