Sar2028, an aspartate/tyrosine/phenylalanine pyridoxal-5'-phosphate-dependent aminotransferase with a molecular weight of 48,168 Da, was overexpressed in methicillin-resistant Staphylococcus aureus compared with a methicillin-sensitive strain. The protein was expressed in Escherichia coli, purified and crystallized. The protein crystallized in a primitive orthorhombic Laue group with unit-cell parameters a = 83.6, b = 91.3, c = 106.0 A, alpha = beta = gamma = 90 degrees. Analysis of the systematic absences along the three principal axes indicated the space group to be P2(1)2(1)2(1). A complete data set was collected to 2.5 A resolution.