1z91
x-ray crystal structure of apo-OhrRC15S in reduced form: MarR family protein
OverviewOverview
The mechanisms by which Bacillus subtilis OhrR, a member of the MarR family of transcription regulators, binds the ohrA operator and is induced by oxidation of its lone cysteine residue by organic hydroperoxides to sulphenic acid are unknown. Here, we describe the crystal structures of reduced OhrR and an OhrR-ohrA operator complex. To bind DNA, OhrR employs a chimeric winged helix-turn-helix DNA binding motif, which is composed of extended eukaryotic-like wings, prokaryotic helix-turn-helix motifs, and helix-helix elements. The reactivity of the peroxide-sensing cysteine is not modulated by proximal basic residues but largely by the positive dipole of helix alpha1. Induction originates from the alleviation of intersubunit steric clash between the sulphenic acid moieties of the oxidized sensor cysteines and nearby tyrosines and methionines. The structure of the OhrR-ohrA operator complex reveals the DNA binding mechanism of the entire MarR family and suggests a common inducer binding pocket.
About this StructureAbout this Structure
1Z91 is a Single protein structure of sequence from Bacillus subtilis. Full crystallographic information is available from OCA.
ReferenceReference
Structure of an OhrR-ohrA operator complex reveals the DNA binding mechanism of the MarR family., Hong M, Fuangthong M, Helmann JD, Brennan RG, Mol Cell. 2005 Oct 7;20(1):131-41. PMID:16209951 Page seeded by OCA on Sat May 3 17:19:45 2008