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 r esistance to beta -lactam antibiotics (penicillins and cephalosporins), has been crystallized. A member of the class D family of serine beta -lactamas es, OXA-1 is especially active against the penicillins oxacillin and cloxac illin and is now found in 10% of E. coli clinical isolates. Crystals grown from PEG 8000 at pH 7.5 diffract to 1.5 Angstrom resolution at 100 K and ha ve space group P1 (Z=2), with unit-cell parameters a=36.0, b=51.6, c=72.9 A ngstrom, alpha =70.2, beta =84.1, gamma =81.5 degrees.