Crystallization and preliminary X-ray study of OXA-1, a class D beta-lactamase.

The Escherichia coli OXA-1 oxacillinase, a beta-lactamase which provides resistance to beta-lactam antibiotics (penicillins and cephalosporins), has been crystallized. A member of the class D family of serine beta-lactamases, OXA-1 is especially active against the penicillins oxacillin and cloxacillin and is now found in 10% of E. coli clinical isolates. Crystals grown from PEG 8000 at pH 7.5 diffract to 1.5 A resolution at 100 K and have space group P1 (Z = 2), with unit-cell parameters a = 36.0, b = 51.6, c = 72.9 A, alpha = 70.2, beta = 84.1, gamma = 81.5 degrees.