Extended Data Fig. 3: MS and 13C-NMR analysis of precyanobacterin I (Z-7) isolated upon supplementation of the expression cultures with 13C5-l-valine.
From: Biosynthesis of cyanobacterin, a paradigm for furanolide core structure assembly
A) Structure of precyanobacterin I (E-7) indicating the positions with 13C-enrichment derived from 13C5-l-valine (blue dots). B) MS analysis of E-7 in cyb heterologous expression extracts after feeding unlabelled l-valine (top) and 13C5-l-valine (bottom). The incorporation of 4 13C atoms derived from l-valine is evident by the +4 shift. C) Comparison of 13C-NMR spectra of precyanobacterin I (Z-7) without (top, black) and with 13C-labelling (bottom, blue) derived from 13C5-l-valine, with expansion of the signals of positions I-III with the expected 13C,13C-coupling pattern.
