3'-O-?-Glucosyl-4',5'-didehydro-5'-deoxyadenosine Is a Natural Product of the Nucleocidin Producers Streptomyces virens and Streptomyces calvus

3'-O-ss-Glucosyl-4',5'-didehydro-5'-deoxyadenosine 13 is identified as a natural product of Streptomyces calvus and Streptomyces virens. It is also generated in vitro by direct ss-glucosylation of 4',5'didehydro-5'-deoxyadenosine 12 with the enzyme NucGT. The intact incorporation of oxygen-18 and deuterium isotopes from (+/-)[1-O-18,1-H-2(2)]-glycerol 14 into C-5' of nucleocidin 1 and its related metabolites precludes 3'-O-ss-glucosyl- 4',5'-didehydro-5'-deoxyadenosine 13 as a biosynthetic precursor to nucleocidin 1.