Crystallization and preliminary crystallographic analysis of IlvC, a ketol-acid reductoisomerase, from Streptococcus pneumoniae

IlvC, a ketol-acid reductoisomerase, plays a critical role in alkyl migration and catalyzes the second step in the biosynthesis of branched amino acids such as leucine, valine and isoleucine. As an initial step to investigate whether IlvC is involved in pneumococcal growth and virulence from the structural background, ilvC from Streptococcus pneumoniae D39 (SpIlvC) was cloned and overexpressed in Escherichia coli. Crystals of SpIlvC were obtained by hanging-drop vapour diffusion in 0.1 M HEPES pH 7.5, 0.1 M NaCl, 1.5 M ammonium sulfate and diffracted to 1.69 Å resolution. The SpIlvC crystal belonged to space group P2 1 2 1 2 1 with unit cell parameters a = 69.1°, b = 104.3°, c = 110.9° and contained two molecules in the asymmetric unit.