Menaquinone biosynthesis: conversion of o-succinylbenzoic acid to 1,4-dihydroxy-2-naphthoic acid and menaquinones by Escherichia coli extracts

Abstract

Two intermediates in the biosynthetic pathway to bacterial menaquinones are o-succinylbenzoic acid and 1,4-dihydroxy-2-naphthoic acid. Cell-free extracts were prepared from E. coli which catalyze the conversion of labeled o-succinylbenzoic acid to the naphthoic acid and also to menaquinones. The naphthoate synthetase was partially purified and required CoA and ATP. The synthetase has a MW of .apprx. 45,000. The conversion of o-succinylbenzoic acid to menaquinones is stimulated by the presence of farnesyl PPi. The major menaquinone produced is then MK-3 (menaquinone with a farnesyl side chain).