Fig. 3: Structures of CgnB and CgnE, affinity measurements and genome mining.
From: Unusual peptide-binding proteins guide pyrroloindoline alkaloid formation in crocagin biosynthesis
a, Overall structure of CgnE. Cartoon representation using the rainbow colour scheme (N terminus, blue; to C terminus, red). b, Metal binding site found in CgnB (yellow) and CgnE (cyan). Two key residues are mutated in CgnE (Glu to Lys and His to Tyr). Zn2+ ions are numbered 1 and 2. c, Table of affinities to investigate substrate binding and complex formation. Components following the ‘+’ are titrated, while the other components are held constant. Representative experiments were repeated independently three times with similar results. d, Sequence of CgnA with residues numbered. Positively charged side chains are highlighted in blue, while the core peptide is in grey. e, Representatives of the five distinct BGC types identified. Common genes are colour-coded. White arrows represent genes with functions not found in all clusters. ABC, ATP-binding cassette; MFS, major facilitator superfamily. Details are reported in Supplementary Tables 4 and 5.
