Open AccessRadiolabelling of the monate moiety in the study of pseudomonic acid biosynthesis
Author(s) -
Mantle Peter G.,
Macgeorge Katharine M.
Publication year - 1989
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1989.tb03082.x
Subject(s) - biosynthesis , ethionine , biochemistry , chemistry , metabolite , stereochemistry , methionine , moiety , coenzyme a , reductase , amino acid , enzyme
Monic acid A was isolated from a Pseudomonas fluorescens fermentation in which pseudomonic acid A (PA) was the principal secondary metabolite. [3‐ 14 C]3‐Hydroxy‐3‐methyl‐glutaric acid (HMG) given early in the idiophase radiolabelled PA (1.1% incorporation), confirming experimentally the putative direct involvement of HMG in the biosynthesis of PA, but contributed relatively insignificant radiolabel to the monic acid extracted from the broth at the end of the fermentation. Ethionine inhibited (80%) PA biosynthesis and correspondingly reduced incorporation of [ 14 C]HMG. In contrast, ethionine increased incorporation of [methyl‐ 14 C]methionine into PA and enhanced specific radioactivity of the antibiotic 8‐fold. Ethionine inhibition of secondary metabolite methylations did not divert pseudomonate biosynthesis to give unusual analogues, implying that methylation of a putative pentaketide precursor of the monate moiety forms a vital intermediate of the pseudomonate pathway, but caused a new [ 14 C]HMG‐derived polar metabolite of biosynthetic interest to become evident.