Sequence analysis of the Brevibacterium lactofermentum trp operon

Abstract

Brevibacterium lactofermentum, a Gram-positive bacterium, is a commercially important amino acid producer. In this organism, the tryptophan biosynthetic enzymes are encoded within a 7725 bp HapII-BamHI fragment. Seven open reading frames were identified as trp genes by complementation tests with various B. lactofermentum and Escherichia coli tryptophan auxotrophs. Following the nomenclature established for E. coli and Serratia marcescens, the B. lactofermentum trp genes were designated trpL, trpE, trpG, trpD, trpC (including the trpF domain), trpB, and trpA. The organization of these genes is identical to that in S. marcescens. The nucleotide sequences of the putative ribosome-binding sites for the B. lactofermentum trp genes resemble those of E. coli and Bacillus subtilis. Computer analysis revealed that the trp enzymes of B. lactofermentum resemble the enzymes of the Gram-negative E. coli more closely than those of the Gram-positive B. subtilis.