Crystallization and preliminary X-ray analysis of human placental S-adenosylhomocysteine hydrolase

Abstract

A recombinant form of human placental S-adenosylhomocysteine (AdoHcy) hydrolase expressed in E. coli, which was inactivated by a type-I mechanism-based inhibitor, has been crystallized using the hanging-drop vapour-diffusion technique. The crystals grow as fiat plates, with unit-cell dimensions a=96.2, b=173.6, c=142.9A, ct=fl=7=90 °. The crystals exhibit the symmetry of space group C222 and diffract to a minimum spacing of "-~ 2.0 A resolution at the Cornell High Energy Synchrotron Source. On the basis of density calculations two monomers of the tetrameric protein are estimated to be present in the asymmetric unit (Vm = 2.99 ,~3 Da-l). The selfrotation function clearly indicates the location of the noncrystallographic twofold axis.