Structure of an OhrR-ohrA operator complex reveals the DNA binding mechanism of the MarR family.

Published

Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Hong, M; Fuangthong, M; Helmann, JD; Brennan, RG

Published Date

  • October 7, 2005

Published In

Volume / Issue

  • 20 / 1

Start / End Page

  • 131 - 141

PubMed ID

  • 16209951

Pubmed Central ID

  • 16209951

International Standard Serial Number (ISSN)

  • 1097-2765

Digital Object Identifier (DOI)

  • 10.1016/j.molcel.2005.09.013

Language

  • eng

Conference Location

  • United States