Crystallization and preliminary X-ray diffraction analysis of protein L-isoaspartyl O-methyltransferase from wheat germ

Wheat-germ protein L-isoaspartyl O-methyltransferase (WPIMT) can initiate t he conversion of L-isoaspartyl residues in a protein or peptide, which accu mulate during the aging process in wheat-germ seeds, to normal l-aspartyl g roups. The recombinant protein of WPIMT was overexpressed in Escherichia co li and purified to homogeneity. The protein was crystallized in the presenc e of S-adenosine-L-homocysteine using 2-methyl-2,4-pentanediol. Preliminary X-ray analysis indicated a tetragonal space group P4(1)2(1)2 or P4(3)2(1)2 , with unit-cell parameters a = b = 77.3, c = 152.9 Angstrom for cryofrozen crystals at 90 K. The crystals diffracted to 3.3 Angstrom and contain two molecules per asymmetric unit.