Crystallization of the Bacillus cereus 5/B/6 Metallo-β-lactamase

β-lactamases pose a great threat in clinical settings due to their resistance to classical antibiotics. The worst offenders of this group include class B β-lactamases, which are metal dependent enzymes. They require one or two zinc ions for optimal activity. Bacillus cereus 5/B/6 produces a metallo-β-lactamase that has not previously had its structure reported. Structural information is crucial for determining the chemical mechanism of action of the enzyme inhibitors.

The research conducted involved finding proper conditions in which 5/B/6 metallo-β-lactamase would produce crystals suitable buffer for further x-ray diffraction studies The ideal conditions were in bis-tris propane with a pH range from 7.5 to 8.5, and a range of 5% to 10% polyethylene glycol (PEG) 5000 monomethyl ether (MME). The
initial x-ray diffracted crystals were grown in 0.1 M bis-tris propane pH 8.5 with 6% PEG 5000 MME. The current diffraction led to a structure of 2.7 Å resolution structure under these conditions.