title: Stereospecificity of hydride transfer in NAD+-catalyzed 2-deoxy-scyllo-inosose synthase, the key enzyme in the biosynthesis of 2-deoxystreptamine-containing aminocyclitol antibiotics.
abstract: The key enzyme in the biosynthesis of clinically important aminocyclitol antibiotics is 2-deoxy-scyllo-inosose synthase (DOIS), which converts ubiquitous d-glucose 6-phosphate (G-6-P) into the specific carbocycle, 2-deoxy-scyllo-inosose with an aid of NAD(+)-NADH recycling. The NAD(+)-dependent first step of the DOIS reaction was examined in detail by the use of 6-phosphonate and 6-homophosphonate analogs of G-6-P. Both analogs showed competitive inhibition against the DOIS reaction with K(i) values of 1.3 and 2.8 mM, respectively, due to their inability for the subsequent phosphate elimination. Based on the direct spectrophotometric observation of NADH formed by the hydride transfer from 6-phosphonate to NAD(+), the stereospecificity of the hydride transfer in the DOIS reaction was analyzed with 6-[4-(2)H]phosphonate and was found to be pro-R specific.
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama, Japan.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huang
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kakinuma
authors.forename: Tadashi
authors.initials: T
authors.lastname: Eguchi
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000737:chemistry; D002384:Catalysis; D019298:Glucose-6-Phosphate / Q000031:analogs & derivatives; D006595:Hexosamines / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D008190:Lyases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D008968:Molecular Conformation; D009243:NAD / Q000737:chemistry* / Q000378:metabolism; D063065:Organophosphonates / Q000737:chemistry; D013379:Substrate Specificity
chemical_list: D000900:Anti-Bacterial Agents; D006595:Hexosamines; D063065:Organophosphonates; D009243:NAD; D019298:Glucose-6-Phosphate; D006859:Hydrogen; D008190:Lyases; C085631:2-deoxy-scyllo-inosose synthase; C007265:2-deoxystreptamine