Figure 4.

Chemical capture of biosynthetic intermediates reveals order and timing of biosynthesis. A) Cysteamine cleavage of thioester-linked intermediates and subsequent derivatization by Fmoc-Cl. B) Mass spectra of intermediates captured in the one-pot assays using AmbE S1958A. MS peaks are colored to match the corresponding compounds captured under different assay conditions. Both the sodium and proton adducts are observed for derivatized 4, but only the sodium adduct is shown for clarity. Extended mass range is shown in the Supporting Information, Figure S10.