Open AccessStructural Analysis and Insights into the Oligomeric State of an Arginine-Dependent Transcriptional Regulator from Bacillus halodurans
Author(s) -
Young Woo Park,
Joongoo Kang,
Hyun Ku Yeo,
Jae Young Lee
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0155396
Subject(s) - repressor , arginine , chemistry , biochemistry , bacillus subtilis , biology , microbiology and biotechnology , transcription factor , gene , genetics , amino acid , bacteria
The arginine repressor (ArgR) is an arginine-dependent transcription factor that regulates the expression of genes encoding proteins involved in the arginine biosynthesis and catabolic pathways. ArgR is a functional homolog of the arginine-dependent repressor/activator AhrC from Bacillus subtilis , and belongs to the ArgR/AhrC family of transcriptional regulators. In this research, we determined the structure of the ArgR (Bh2777) from Bacillus halodurans at 2.41 Å resolution by X-ray crystallography. The ArgR from B . halodurans appeared to be a trimer in a size exclusion column and in the crystal structure. However, it formed a hexamer in the presence of L-arginine in multi-angle light scattering (MALS) studies, indicating the oligomerization state was dependent on the presence of L-arginine. The trimeric structure showed that the C-terminal domains form the core, which was made by inter-subunit interactions mainly through hydrophobic contacts, while the N-terminal domains containing a winged helix-turn-helix DNA binding motif were arranged around the periphery. The arrangement of trimeric structure in the B . halodurans ArgR was different from those of other ArgR homologs previously reported. We finally showed that the B . halodurans ArgR has an arginine-dependent DNA binding property by an electrophoretic mobility shift assay.