In Vitro Characterization of Echinomycin Biosynthesis: Formation and Hydroxylation of L-Tryptophanyl-S-Enzyme and Oxidation of (2S,3S) β-Hydroxytryptophan
Figure 3
Proposed biosynthetic pathway for QXC produced by
S. griseovariabilis. The biosynthesis of QXC is a part of that of echinomycin. L-Trp: L-tryptophan; L-Trp-S-Qui18: L-tryptophanyl-S-Qui18; (2S,3S) hTrp-S-Qui18: (2S,3S) β-hydroxytryptophanyl-S-Qui18; (2S,3S) hTrp: (2S,3S) β-hydroxytryptophan; (2S,3R) hNFK: (2S,3R) N-formyl-β-hydroxykynurenine; QXC: quinoxaline-2-carboxylic acid.