Crystallization and preliminary X-ray diffraction studies of aclacinomycin-10-methyl esterase and aclacinomycin-10-hydroxylase from Streptomyces purpurascens.
Two enzymes participating in the biosynthesis of anthracyclines in Streptomyces purpurascens, aclacinomycin-10-methyl esterase (RdmC) and aclacinomycin-10-hydroxylase (RdmB), have been crystallized. RdmB is a S-adenosyl-methionine-dependent hydroxylase and RdmC hydrolyses the carboxymethyl group of the aglycone skeleton of aclacinomycin. Crystals of RdmB obtained in the presence of S-adenosyl-L-methionine were orthorhombic, space group C222(1), with unit-cell parameters a = 63.2, b = 92.2, c = 115.3 A; diffraction data were collected to 2.1 A resolution. RdmC was crystallized as a complex with the substrate, aclacinomycin T. These crystals diffracted to 1.45 A resolution and belonged to space group P2(1), with unit-cell parameters a = 38.2, b = 84.7, c = 44.3 A, beta = 99.9 degrees.