13C NMR spectrum of the AetD-catalysed reaction in the presence of [2-13C]-5,7-dibromo-l-tryptophan (7). In the full reaction assay, the C2 peak corresponding to substrate 7 disappeared, whereas two new 13C peaks appeared, which we characterized as the alcohol and aldehyde carbons of 11 and 12, respectively. Asterisks represent glycerol peaks from the AetD protein stock.
