Fig. 2: Proposed biosynthetic route to 8-azaguanine (1) based on this study.
From: Nitric oxide as a source for bacterial triazole biosynthesis
The GCH I-like enzyme PtnA is proposed to catalyze the hydrolytic cleavage of C8 of GTP. The resulting product 2,5-diaminopyrimidine triphosphate could combine with a NO-derived reactive species to afford 8-azaguanosine triphosphate (8), and followed by pyrophosphate release by host enzyme(s). Alternatively, the compound 2,5-diaminopyrimidine triphosphate could first undergo pyrophosphate release and then followed by triazole formation to afford 4.
