Open AccessA high‐resolution structure of the DNA‐binding domain of AhrC, the arginine repressor/activator protein from Bacillus subtilis
Author(s) -
Garnett James A.,
Baumberg Simon,
Stockley Peter G.,
Phillips Simon E. V.
Publication year - 2007
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309107048166
Subject(s) - repressor , bacillus subtilis , operon , dna , dna binding domain , recombinant dna , arginine , biochemistry , helix turn helix , protein subunit , biology , chemistry , microbiology and biotechnology , gene , escherichia coli , amino acid , transcription factor , genetics , bacteria
In Bacillus subtilis the concentration of l ‐arginine is controlled by the transcriptional regulator AhrC, which interacts with 18 bp DNA operator sites called ARG boxes in the promoters of arginine biosynthetic and catabolic operons. AhrC is a 100 kDa homohexamer, with each subunit having two domains. The C‐terminal domains form the core, mediating intersubunit interactions and binding of the co‐repressor l ‐arginine, whilst the N‐terminal domains contain a winged helix–turn–helix DNA‐binding motif and are arranged around the periphery. The N‐terminal domain of AhrC has been expressed, purified and characterized and it has been shown that the fragment still binds DNA operators as a recombinant monomer. The DNA‐binding domain has also been crystallized and the crystal structure refined to 1.0 Å resolution is presented.