skip to main content

Title: Structures of the Porphyromonas gingivalis OxyR regulatory domain explain differences in expression of the OxyR regulon in Escherichia coli and P. gingivalis

Differences in OxyR regulated expression of oxidative stress genes between Escherichia coli and Porphyromonas gingivalis are explained by very minor differences in structure and amino-acid sequence of the respective oxidized and reduced OxyR regulatory domains. These differences affect OxyR quaternary structures and are predicted from model building of full length OxyR–DNA complexes to confer distinct modes of DNA binding on this transcriptional regulator. OxyR transcriptionally regulates Escherichia coli oxidative stress response genes through a reversibly reducible cysteine disulfide biosensor of cellular redox status. Structural changes induced by redox changes in these cysteines are conformationally transmitted to the dimer subunit interfaces, which alters dimer and tetramer interactions with DNA. In contrast to E. coli OxyR regulatory-domain structures, crystal structures of Porphyromonas gingivalis OxyR regulatory domains show minimal differences in dimer configuration on changes in cysteine disulfide redox status. This locked configuration of the P. gingivalis OxyR regulatory-domain dimer closely resembles the oxidized (activating) form of the E. coli OxyR regulatory-domain dimer. It correlates with the observed constitutive activation of some oxidative stress genes in P. gingivalis and is attributable to a single amino-acid insertion in P. gingivalis OxyR relative to E. coli OxyR. Modelling of full-length P. gingivalis, E. coli andmore » Neisseria meningitidis OxyR–DNA complexes predicts different modes of DNA binding for the reduced and oxidized forms of each.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ; ;  [1] ;  [3] ;  [2] ;  [2]
  1. Virginia Commonwealth University, Richmond, VA 23298-0566 (United States)
  2. (United States)
  3. Virginia Commonwealth University, Richmond, VA 23219-1540 (United States)
Publication Date:
OSTI Identifier:
22351296
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography; Journal Volume: 69; Journal Issue: Pt 10; Other Information: PMCID: PMC3792645; PMID: 24100327; PUBLISHER-ID: cb5032; OAI: oai:pubmedcentral.nih.gov:3792645; Copyright (c) International Union of Crystallography 2013; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CONFIGURATION; CRYSTAL STRUCTURE; CYSTEINE; DIMERS; DNA; DOMAIN STRUCTURE; ESCHERICHIA COLI; INTERACTIONS; INTERFACES; LENGTH