1F9N

CRYSTAL STRUCTURE OF AHRC, THE ARGININE REPRESSOR/ACTIVATOR PROTEIN FROM BACILLUS SUBTILIS

Summary for 1F9N

• Entry DOI: 10.2210/pdb1f9n/pdb
• Descriptor: ARGININE REPRESSOR/ACTIVATOR PROTEIN (2 entities in total)
• Functional Keywords: winged-helix-turn-helix, arginine repressor, dna binding protein
• Biological source: Bacillus subtilis
• Cellular location: Cytoplasm: P17893
• Total number of polymer chains: 6
• Total formula weight: 101126.87

Authors

Dennis, C.A.,Glykos, N.M.,Parsons, M.R.,Phillips, S.E.V. (deposition date: 2000-07-11, release date: 2002-02-27, Last modification date: 2024-02-07)

Primary citation

Dennis C, C.A.,Glykos, N.M.,Parsons, M.R.,Phillips, S.E.
The structure of AhrC, the arginine repressor/activator protein from Bacillus subtilis.
Acta Crystallogr.,Sect.D, 58:421-430, 2002

PubMed Abstract: In the Gram-positive bacterium Bacillus subtilis the concentration of the amino acid L-arginine is controlled by the transcriptional regulator AhrC. The hexameric AhrC protein binds in an L-arginine-dependent manner to pseudo-palindromic operators within the promoter regions of arginine biosynthetic and catabolic gene clusters. AhrC binding results in the repression of transcription of biosynthetic genes and in the activation of transcription of catabolic genes. The crystal structure of AhrC has been determined at 2.7 A resolution. Each subunit of the protein has two domains. The C-terminal domains are arranged with 32 point-group symmetry and mediate the major intersubunit interactions. The N-terminal domains are located around this core, where they lie in weakly associated pairs but do not obey strict symmetry. A structural comparison of AhrC with the arginine repressor from the thermophile B. stearothermophilus reveals close similarity in regions implicated in L-arginine binding and DNA recognition, but also reveals some striking sequence differences, especially within the C-terminal oligomerization domain, which may contribute to the different thermostabilities of the proteins. Comparison of the crystal structure of AhrC with a 30 A resolution model obtained by combining X-ray structure-factor amplitudes with phases derived from electron-microscopic analyses of AhrC crystals confirms the essential accuracy of the earlier model and suggests that such an approach may be more widely useful for obtaining low-resolution phase information.

PubMed: 11856827
DOI: 10.1107/S0907444901021692

Experimental method

X-RAY DIFFRACTION (2.7 Å)