Mechanism and stereochemistry of the biosynthesis of 2-deoxystreptamine and neosamine C.
Feeding experiments with D-[6,6-2H2]-, D-(6R)-[6-2H1]- and D-(6S)-[6-2H1]glucose in the fermentation of Streptomyces ribosidificus, followed by field desorption MS and 2H NMR analyses of the resulting labeled ribostamycin samples, clearly demonstrated that 1) both hydrogens of the C-6 hydroxymethyl group of D-glucose are stereospecifically incorporated into the C-2 position of 2-deoxystreptamine and 2) the pro S hydrogen of the C-6 position of D-glucose is stereospecifically removed during the elaboration of neosamine C in the biosynthesis of ribostamycin. A plausible mechanism of formation of the deoxy-scyllo-inosose, an early precursor to 2-deoxystreptamine, is suggested to be analogous to the dehydroquinate synthesis in the shikimate pathway and the conversion of the C-6 hydroxymethyl group of D-glucose into the aminomethyl group of neosamine C is likely to involve a dehydrogenation step to a formyl group.
Kakinuma
K
K
Laboratory of Chemistry for Natural Products, Tokyo Institute of Technology, Yokohama, Japan.
Ogawa
Y
Y
Sasaki
T
T
Seto
H
H
Otake
N
N
D000900:Anti-Bacterial Agents / Q000032:analysis / Q000096:biosynthesis*; D055598:Chemical Phenomena; D002621:Chemistry; D005285:Fermentation; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000096:biosynthesis; D006595:Hexosamines / Q000032:analysis / Q000096:biosynthesis; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013302:Streptomyces / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D006595:Hexosamines; C038761:neosamine C; C007265:2-deoxystreptamine; D005944:Glucosamine