Evidence of adaptability in metal coordination geometry and active-site loop conformation among B1 metallo-[beta]-lactamases

A high-resolution structure of enzyme Co(II)-BcII from Bacillus cereus which revealed a metal coordination geometry identical to that of the native zinc enzyme dependent [beta]-lactamase is presented. A considerable flexibility observed in the two loops of Cys ligand containing four metal ligands could assist in the in the structural rearrangement of the metal sites during catalytic turnover, which, along with the coordination geometry adaptability of Zn(II) ions, grants the interaction with a variety of substrates, a characteristic feature of B1 metallo-[beta[-lactamases.