Fig. 1: Biosynthetic investigation of 8-azaguanine (1).
From: Nitric oxide as a source for bacterial triazole biosynthesis
a The structures of 1,2,3-triazole, 8-azaguanine (1) and guanine. b The biosynthetic gene cluster (ptn cluster) of 8-azaguanine. c Heterologous expression and in vivo reconstitution of the 1 biosynthetic pathway in S. albus J1074. The extracted ion chromatograms (EIC) for 1 (m/z 151, [M−H]−), 2 (m/z 152, [M−H]−), 3 (m/z 283, [M−H]−) from LC-MS analysis were presented. Note: three independent tests were taken, the ratio of 1 to 2 varies from batches to batches, which could be attributed to the fluctuation of host metabolism, as 2 derives from 1 by a host enzyme (guanine deaminase). d LC-HR-ESI-MS analysis of 8-azaguanine (1) and 8-azaxanthine (2) from stable isotope-labeled precursors feeding experiments. e Isotope-labeling pattern of 1 and 2 based on results from (d).
