Structural analysis of the DNA-binding domain of the Helicobacter pylori response regulator ArsR.

Gupta SS, Borin BN, Cover TL, Krezel AM
J Biol Chem. 2009 284 (10): 6536-45

PMID: 19117956 · PMCID: PMC2649097 · DOI:10.1074/jbc.M804592200

The Helicobacter pylori ArsS-ArsR two-component signal transduction system, comprised of a sensor histidine kinase (ArsS) and a response regulator (ArsR), allows the bacteria to regulate gene expression in response to acidic pH. We expressed and purified the full-length ArsR protein and the DNA-binding domain of ArsR (ArsR-DBD), and we analyzed the tertiary structure of the ArsR-DBD using solution nuclear magnetic resonance (NMR) methods. Both the full-length ArsR and the ArsR-DBD behaved as monomers in size exclusion chromatography experiments. The structure of ArsR-DBD consists of an N-terminal four-stranded beta-sheet, a helical core, and a C-terminal beta-hairpin. The overall tertiary fold of the ArsR-DBD is most closely related to DBD structures of the OmpR/PhoB subfamily of bacterial response regulators. However, the orientation of the N-terminal beta-sheet with respect to the rest of the DNA-binding domain is substantially different in ArsR compared with the orientation in related response regulators. Molecular modeling of an ArsR-DBD-DNA complex permits identification of protein elements that are predicted to bind target DNA sequences and thereby regulate gene transcription in H. pylori.

MeSH Terms (14)

Bacterial Proteins DNA, Bacterial Gene Expression Regulation, Bacterial Helicobacter pylori Histidine Kinase Hydrogen-Ion Concentration Models, Molecular Nuclear Magnetic Resonance, Biomolecular Protein Kinases Protein Structure, Secondary Protein Structure, Tertiary Signal Transduction Trans-Activators Transcription, Genetic

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