Esmeraldin Biosynthesis
Phenazine derivatives are common products of a number of bacteria,
especially various Pseudomonas species. A particular strain of
Streptomyces antibioticus is notable for the production of dimeric
phenazines, green pigments called esmeraldins (Structure 1), in
addition to the simpler monomeric saphenamycins (Structure 2). Our
group has been studying the biosynthesis of these compounds through
feeding experiments with isotopically labeled precursors. The
phenazine ring system is derived from the shikimate pathway, but the
exact nature of the shikimate metabolite which dimerizes to the
tricyclic phenazine ring system is unknown. Identification of this
precursor, presumably a compound identical with or related to
anthranilic acid, is a major goal of our work, as is the understanding
of the dimerization mechanism by which two molecules of a saphenic
acid derivative gives rise to the esmeraldin skeleton.
