Structural mechanism of organic hydroperoxide induction of the transcription regulator OhrR.

Journal Article (Journal Article)

The Xanthomonas campestris transcription regulator OhrR contains a reactive cysteine residue (C22) that upon oxidation by organic hydroperoxides (OHPs) forms an intersubunit disulphide bond with residue C127'. Such modification induces the expression of a peroxidase that reduces OHPs to their less toxic alcohols. Here, we describe the structures of reduced and OHP-oxidized OhrR, visualizing the structural mechanism of OHP induction. Reduced OhrR takes a canonical MarR family fold with C22 and C127' separated by 15.5 A. OHP oxidation results in the disruption of the Y36'-C22-Y47' interaction network and dissection of helix alpha5, which then allows the 135 degrees rotation and 8.2 A translation of C127', formation of the C22-C127' disulphide bond, and alpha6-alpha6' helix-swapped reconfiguration of the dimer interface. These changes result in the 28 degrees rigid body rotations of each winged helix-turn-helix motif and DNA dissociation. Similar effector-induced rigid body rotations are expected for most MarR family members.

Full Text

Duke Authors

Cited Authors

  • Newberry, KJ; Fuangthong, M; Panmanee, W; Mongkolsuk, S; Brennan, RG

Published Date

  • November 30, 2007

Published In

Volume / Issue

  • 28 / 4

Start / End Page

  • 652 - 664

PubMed ID

  • 18042459

International Standard Serial Number (ISSN)

  • 1097-2765

Digital Object Identifier (DOI)

  • 10.1016/j.molcel.2007.09.016


  • eng

Conference Location

  • United States