Wheat-germ protein L-isoaspartyl O-methyltransferase (WPIMT) can initiate the conversion of L-isoaspartyl residues in a protein or peptide, which accumulate during the aging process in wheat-germ seeds, to normal L-aspartyl groups. The recombinant protein of WPIMT was overexpressed in Escherichia coli and purified to homogeneity. The protein was crystallized in the presence of S-adenosine-L-homocysteine using 2-methyl-2,4-pentanediol. Preliminary X-ray analysis indicated a tetragonal space group P41212 or P43212, with unit-cell parameters a = b = 77.3, c = 152.9 Å for cryofrozen crystals at 90 K. The crystals diffracted to 3.3 Å and contain two molecules per asymmetric unit.
