Crystallization and preliminary X-ray diffraction study of the class A beta-lactamase SED-1 and its mutant SED-G238C...

SED-1, a class A beta-lactamase from Citrobacter sedlakii, is a CTX-M-type extended-spectrum beta-lactamase that has the ability to hydrolyze expanded-spectrum cephalosporins such as cefotaxime. SED-1 and a SED mutant in which Gly238 has been replaced by a cysteine, forming a disulfide bridge with the other Cys residue located at position 69 (SED-G238C), have been crystallized. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 188.09, b = 73.65, c = 105.41 A, beta = 121.67 degrees for SED-1 and a = 187.64, b = 73.2, c = 103.89 A, beta = 121.89 degrees for the SED-G238C mutant. X-ray diffraction data were collected to maximum resolutions of 2.4 A for SED-1 and 2.0 A for SED-G238C.