3nhz
From Proteopedia
Structure of N-terminal Domain of MtrA
Structural highlights
FunctionMTRA_MYCTU Member of the two-component regulatory system MtrA/MtrB. Binds direct repeat motifs of sequence 5'-GTCACAGCG-3', phosphorylation confers higher affinity. Overexpression decreases bacteria viability upon infection of human THP-1 macrophage cell line, due at least in part to impaired blockage of phagosome-lysosome fusion (upon infection bacteria usually remain in phagosomes). Infecting C57BL/6 mice with an overexpressing strain leads to an attentuated infection in both spleen and lungs. The level of dnaA mRNA increases dramatically. Binds the promoter of dnaA, fbpD, ripA and itself, as well as oriC, which it may regulate. Upon co-overexpression of MrtA and MtrB growth in macrophages is partially restored, dnaA expression is not induced, although mouse infections are still attenuated, suggesting that bacterial growth in macrophages requires an optimal ratio of MtrB to MtrA.[1] [2] [3] 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 PubMedDNA-binding response regulators of the OmpR/PhoB subfamily alternate between inactive and active conformational states, with the latter having enhanced DNA-binding affinity. Phosphorylation of an aspartate residue in the receiver domain, usually via phosphotransfer from a cognate histidine kinase, stabilizes the active conformation. Many of the available structures of inactive OmpR/PhoB family proteins exhibit extensive interfaces between the N-terminal receiver and C-terminal DNA-binding domains. These interfaces invariably involve the alpha4-beta5-alpha5 face of the receiver domain, the locus of the largest differences between inactive and active conformations and the surface that mediates dimerization of receiver domains in the active state. Structures of receiver domain dimers of DrrB, DrrD and MtrA have been determined and phosphorylation kinetics analyzed. Analysis of phosphotransfer from small molecule phosphodonors has revealed large differences in autophosphorylation rates among OmpR/PhoB response regulators. Response regulators with substantial domain interfaces exhibit slow rates of phosphorylation. Rates are greatly increased in isolated receiver domain constructs. Such differences are not observed between autophosphorylation rates of full-length and isolated receiver domain of a response regulator that lacks interdomain interfaces nor are they observed in histidine kinase-mediated phosphotransfer. These findings suggest that domain interfaces restrict receiver domain conformational dynamics, stabilizing an inactive conformation that is catalytically incompetent for phosphotransfer from small molecule phosphodonors. Inhibition of phosphotransfer by domain interfaces provides an explanation for the observation that some response regulators cannot be phosphorylated by small molecule phosphodonors in vitro and provides a potential mechanism for insulating some response regulators from small molecule-mediated phosphorylation in vivo. Regulation of response regulator autophosphorylation through interdomain contacts.,Barbieri CM, Mack TR, Robinson VL, Miller MT, Stock AM J Biol Chem. 2010 Aug 11. PMID:20702407[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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