Extended Data Fig. 5: 13C-NMR analysis to identify acyloin intermediate 9 utilizing labelling experiments with 13C9-l-tyrosine and 13C5-l-valine.
From: Biosynthesis of cyanobacterin, a paradigm for furanolide core structure assembly
Acyloins such as 9 are notoriously difficult to isolate and characterize or to be detected by mass spectrometry9. Thus, to determine the structure of 9, labelled amino acid precursors were fed to expression cultures and the raw extract was analysed by 13C-NMR. Three separate experiments a-c were conducted, applying (a) both 13C9-l-tyrosine and 13C5-l-valine (top, black), (b) 13C9-l-tyrosine (middle, red), or 13C5-l-valine (bottom, blue). Comparison of expression cultures allowed assignment of the proposed decarboxylated acyloin intermediate 9.
