Novel a-L-Rhamnopyranosides from a single strain of streptomyces by supplement-induced biosynthetic steps

摘要

Various acyl and phenyl alpha-L-rhamnopyranosides were produced by Streptomyces griseoviridis (strain Tu 3634) in the presence of different supplements.Some of theadded aromatic compounds underwent structural transformation sprior to rhamnosylation (1,3,5,8,9).Especially remarkable was the formation of an indole (9).Especially remarkable was the formation of an indole(9) when 3,5-diaminobenzoic acid was added.Other precursors were not acepted by the strain,but did induceor enhance the biosynthesis of aromatic carboxylic acids from the shikimate pathway.These acids were hen transformed into the acyl alpha-L-rhamnopyranosides 10-13.This can be seen as a new strategy of pathway engineering.With derivatives 4 and 14-17 we gained further insight into the substrate specificity of hte rhamnosylatransferase,inparticular concerning the competition ofr rhamnosylation between a carboxylic acid and a phenolor aliphatic hydroxyl groups.All isolated meabolites wee detected by chemical screening and characterized by spectroscopic methods.The biosynthetic abilities of the strain result in a remarkable sructural dieversity within the family of alpha-L-rhamnopyranosides.The strain exemplifies theone strain/many compounds (OSMAC) approach.