title: Crystallization of a type III chloramphenicol acetyl transferase.
abstract: A type III variant of chloramphenicol acetyl transferase was purified from Escherichia coli and crystallized in the presence of cobaltic hexamine chloride and 2-methyl-2, 4-pentandiol. Two crystal forms were obtained, one of which proved to be suitable for high-resolution X-ray diffraction studies. The space group of this form is R32 with aR = 74.5 A, alpha R = 92.5 degrees, with a monomer (Mr 25,000) in the asymmetric unit. The crystals diffract to 1.7 A resolution. The crystal symmetry has led to a re-evaluation of the oligomeric symmetry of the enzyme and the proposal that it is a trimer rather than a tetramer, the quaternary structure predicted previously from studies of the association of hybrid s subunits.
mesh_terms: D000123:Acetyltransferases; D015500:Chloramphenicol O-Acetyltransferase; D003460:Crystallization; D004926:Escherichia coli / Q000201:enzymology; D014961:X-Ray Diffraction
chemical_list: D000123:Acetyltransferases; D015500:Chloramphenicol O-Acetyltransferase