Fig. 5.

AIR is the direct precursor of 5-OHBza. (A) LC-MS/MS analysis of corrinoid extracts of purine biosynthesis mutants. The indicated E. coli strains were grown with Cbi and ¹⁵NH₄Cl, and corrinoid extracts were analyzed for the presence of [¹⁵N₁, ¹⁵N₃-DMB]-B₁₂ (doubly charged m/z of 679.2, product ion DMB m/z 149.1). (B) In vitro analysis of 5-OHBza biosynthesis. HPLC analysis of the in vitro reconstitution reaction of G. sulfurreducens BzaF with AIR, SAM, and dithionite shows the formation of a product that coelutes with a standard of 5-OHBza. Control reactions with one component omitted are also shown. (C) The extracted ion chromatogram of 5-OHBza (m/z 135.1) from the LC-MS analysis of the in vitro reconstitution reaction of G. sulfurreducens BzaF with AIR, SAM, and dithionite. (D) UV-Vis spectroscopy of the BzaF reaction product. The HPLC-purified G. sulfurreducens BzaF reaction product is overlaid with that of a standard sample of 5-OHBza.