Export of L-isoleucine from Corynebacterium glutamicum: a two-gene-encoded member of a new translocator family.

ABSTRACT: Bacteria possess amino acid export systems, and Corynebacterium glutamicum excretes L-isoleucine in a process dependent on the proton motive force. In order to identify the system responsible for L-isoleucine export, we have used transposon mutagenesis to isolate mutants of C. glutamicum sensitive to the peptide isoleucyl-isoleucine. In one such mutant, strong peptide sensitivity resulted from insertion into a gene designated brnF encoding a hydrophobic protein predicted to possess seven transmembrane spanning helices. brnE is located downstream of brnF and encodes a second hydrophobic protein with four putative membrane-spanning helices. A mutant deleted of both genes no longer exports L-isoleucine, whereas an overexpressing strain exports this amino acid at an increased rate. BrnF and Br

SUBMITTER: Kennerknecht N 

PROVIDER: S-EPMC135157 | biostudies-literature | 2002 Jul

REPOSITORIES: biostudies-literature