STRUCTURE NOTE The 1.6-Å Resolution Crystal Structure of NovW: A 4-Keto-6- deoxy Sugar Epimerase from the Novobiocin Biosynthetic Gene Cluster of Streptomyces spheroides

Introduction. The aminocoumarin antibiotics novobio-cin, clorobiocin, and coumermycin A1 are Streptomyces natural products. Despite their potency against Gram-positive bacteria, only novobiocin has seen limited clinical use because of toxicity problems and poor pharmacokinet