Crystallization and X-ray analysis of the Y75N mutant of Mucor pusillus pepsin complexed with inhibitor

Y75N mutant Mucor pusillus pepsin has been overexpressed in yeast, purified and cocrystallized with the iodine-containing human renin inhibitor CP-113972 {(2R,3S)-isopropyl 3-[(L-prolyl-p-iodo-L-phenylalanyl-S-methyl-cysteinyl)amino-4]-cyclohexyl-2-hydroxybutanoate} for X-ray crystallography. Tetragonal complex crystals with space group P43212 were produced by the hanging-drop vapour-diffusion method and diffracted to 3.0 Å. The crystals exhibited unit-cell parameters a = b = 182.5, c = 99.1 Å and contained four molecules in the asymmetric unit. A 96% complete data set was collected at 298 K using Cu K[alpha] X-rays from a rotating-anode generator. Solution of the crystal structure of Y75N mutant M. pusillus pepsin is under way by molecular replacement using the molecular coordinates of wild-type M. pusillus pepsin as a model.