Open AccessTranscriptional control of the F 0 F 1 ‐ ATP synthase operon of C orynebacterium glutamicum : SigmaH factor binds to its promoter and regulates its expression at different pH values
Author(s) -
BarriusoIglesias Mónica,
Barreiro Carlos,
SolaLanda Alberto,
Martín Juan F.
Publication year - 2013
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.12022
Subject(s) - corynebacterium glutamicum , operon , biology , microbiology and biotechnology , gene , escherichia coli , gene expression , gal operon , biochemistry , promoter , mutant , plasmid
Summary C orynebacterium glutamicum used in the amino acid fermentation industries is an alkaliphilic microorganism. Its F 0 F 1 ‐ ATP ase operon ( atpBEFHAGDC ) is expressed optimally at pH 9.0 forming a polycistronic (7.5 kb) and a monocistronic (1.2 kb) transcripts both starting upstream of the atpB gene. Expression of this operon is controlled by the Sigma H factor. The sigma H gene ( sigH ) was cloned and shown to be co‐transcribed with a small gene, cg0877 , encoding a putative anti‐sigma factor. A mutant deleted in the sigH gene expressed the atpBEFHAGDC operon optimally at pH 7.0 at difference of the wild‐type strain (optimal expression at pH 9.0). These results suggested that the SigmaH factor is involved in pH control of expression of the F 0 F 1 ATP ase operon. The SigmaH protein was expressed in E scherichia coli fused to the GST (glutathione‐ S ‐transferase) and purified to homogeneity by affinity chromatography on a GST rap HP column. The fused protein was identified by immunodetection with anti‐ GST antibodies. DNA ‐binding studies by electrophoretic mobility shift assays showed that the SigH protein binds to a region of the atpB promoter containing the sigma H recognition sequence (−35) TTGGAT …18nt… GTTA (−10). SigmaH plays an important role in the cascade of control of pH stress in C orynebacterium .