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Crystal structure of the bef3-activated receiver domain of redox response regulator arca
Structural highlights
FunctionARCA_ECOLI Member of the two-component regulatory system ArcB/ArcA. Represses a wide variety of aerobic enzymes under anaerobic conditions. Controls the resistance of E.coli to dyes; required for expression of the alkaline phosphatase and sex factor F genes; It also may be involved in the osmoregulation of envelope proteins. When activated by ArcB, it negatively regulates the expression of genes of aerobic function. Activates the transcription of the plfB operon by binding to its promoter. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEscherichia coli react to changes from aerobic to anaerobic conditions of growth using the ArcA-ArcB two-component signal transduction system. This system, in conjunction with other proteins, regulates the respiratory metabolic pathways in the organism. ArcA is a member of the OmpR/PhoB subfamily of response regulator transcription factors that are known to regulate transcription by binding in tandem to target DNA direct repeats. It is still unclear in this subfamily how activation by phosphorylation of the regulatory domain of response regulators stimulates DNA binding by the effector domain and how dimerization and domain orientation, as well as intra- and intermolecular interactions, affect this process. In order to address these questions we have solved the crystal structures of the regulatory domain of ArcA in the presence and absence of the phosphoryl analog, BeF3-. In the crystal structures, the regulatory domain of ArcA forms a symmetric dimer mediated by the alpha4-beta5-alpha5 face of the protein and involving a number of residues that are highly conserved in the OmpR/PhoB subfamily. It is hypothesized that members of this subfamily use a common mechanism of regulation by dimerization. Additional biophysical studies were employed to probe the oligomerization state of ArcA, as well as its individual domains, in solution. The solution studies show the propensity of the individual domains to associate into oligomers larger than the dimer observed for the intact protein, and suggest that the C-terminal DNA-binding domain also plays a role in oligomerization. Structural analysis and solution studies of the activated regulatory domain of the response regulator ArcA: a symmetric dimer mediated by the alpha4-beta5-alpha5 face.,Toro-Roman A, Mack TR, Stock AM J Mol Biol. 2005 May 27;349(1):11-26. Epub 2005 Apr 7. PMID:15876365[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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