Evidence for the conversion of adenosine to 2'-deoxycoformycin by Streptomyces antibioticus

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Abstract
The incorporation and distribution of 14C in 2''-deoxycoformycin, elaborated by S. antibioticus, were studied with [U-14C]glycine, [U-14C]adenosine and [U-14C]adenine. Similar ratios of 14C in the aglycon and carbohydrate portions of 2''-deoxycoformycin, ara-A and adenosine isolated from the RNA indicated that [U-14C]adenosine was incorporated into 2''-deoxycoformycin without cleavage of the N-glycosylic bond. Following the addition of [U-14C]adenine, 98% of the 14C isolated from [14C]-2''-deoxycoformycin resided in the aglycon. 2''-Deoxycoformycin biosynthesis may not require the de novo purine biosynthetic pathway as evidenced by the failure to detect incorporation of [U-14C]glycine into 2''-deoxycoformycin. The biosynthesis of 2''-deoxycoformycin apparently involves the incorporation of the C-N skeleton of an intact purine nucleoside or nucleotide, implying that a purine ring is opened enzymatically between C-6 and N-1 and a I-C unit is added to form the 1,3-diazepine ring of 2''-deoxycoformycin.