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From Proteopedia
Crystal Structure Of The Receiver Domain Of TMAO Respiratory System Response Regulator TorR
Structural highlights
FunctionTORR_ECOLI Member of the two-component regulatory system TorS/TorR involved in the anaerobic utilization of trimethylamine-N-oxide (TMAO). Phosphorylated TorR activates the transcription of the torCAD operon by binding to four decameric boxes located in the torCAD promoter. Box1, 2 and 4 contain the DNA sequence 5'-CTGTTCATAT-3' and box3 contains the DNA sequence 5'-CCGTTCATCC-3'. Phosphorylated as well as unphosphorylated TorR negatively regulates its own expression by binding to box1 and 2. 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 PubMedBacterial response regulators are key regulatory proteins that function as the final elements of so-called two-component signaling systems. The activities of response regulators in vivo are modulated by phosphorylation that results from interactions between the response regulator and its cognate histidine protein kinase. The level of response regulator phosphorylation, which is regulated by intra-or extracellular signals sensed by the histidine protein kinase, ultimately determines the output response that is initiated or carried out by the response regulator. We have recently hypothesized that in the OmpR/PhoB subfamily of response regulator transcription factors, this activation involves a common mechanism of dimerization using a set of highly conserved residues in the alpha4-beta5-alpha5 face. Here we report the X-ray crystal structures of the regulatory domains of response regulators TorR (1.8 A), Ca(2+)-bound KdpE (2.0 A), and Mg(2+)/BeF(3)(-)-bound KdpE (2.2 A), both members of the OmpR/ PhoB subfamily from Escherichia coli. Both regulatory domains form symmetric dimers in the asymmetric unit that involve the alpha4-beta5-alpha5 face. As observed previously in other OmpR/PhoB response regulators, the dimer interfaces are mediated by highly conserved residues within this subfamily. These results provide further evidence that most all response regulators of the OmpR/ PhoB subfamily share a common mechanism of activation by dimerization. A common dimerization interface in bacterial response regulators KdpE and TorR.,Toro-Roman A, Wu T, Stock AM Protein Sci. 2005 Dec;14(12):3077-88. PMID:16322582[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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