Purification, crystallization and preliminary X-ray analysis of the beta-lactamase Oih-1 from Oceanobacillus iheyensis.

Bacterial resistance to the beta-lactam family of antibiotics is primarily the result of the deactivation of the drugs by beta-lactamase enzymes. The gene encoding the proficient beta-lactamase Oih-1 from the alkaliphilic and halotolerant Gram-positive bacterium Oceanobacillus iheyensis has been cloned and the mature wild-type protein (comprising 274 amino-acid residues) has been expressed in Escherichia coli and subsequently purified to homogeneity. Oih-1 crystallized in two crystal forms both belonging to the trigonal space group P3(1)21 but with distinctly different unit-cell parameters. Synchrotron diffraction data were collected to high resolution (1.65-1.75 A) from both crystal forms on beamlines BL7-1 and BL11-1 at SSRL (Stanford, California, USA).