2v9a
Structure of Citrate-free Periplasmic Domain of Sensor Histidine Kinase CitAStructure of Citrate-free Periplasmic Domain of Sensor Histidine Kinase CitA
Structural highlights
FunctionCITA_KLEPN Member of the two-component regulatory system CitA/CitB. Probably activates CitB by phosphorylation. The periplasmic domain binds H-citrate(2-), which is essential for induction of the citrate-fermentation genes.[1] 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 PubMedSensor histidine kinases of two-component signal-transduction systems are essential for bacteria to adapt to variable environmental conditions. However, despite their prevalence, it is not well understood how extracellular signals such as ligand binding regulate the activity of these sensor kinases. CitA is the sensor histidine kinase in Klebsiella pneumoniae that regulates the transport and anaerobic metabolism of citrate in response to its extracellular concentration. We report here the X-ray structures of the periplasmic sensor domain of CitA in the citrate-free and citrate-bound states. A comparison of the two structures shows that ligand binding causes a considerable contraction of the sensor domain. This contraction may represent the molecular switch that activates transmembrane signaling in the receptor. A ligand-induced switch in the periplasmic domain of sensor histidine kinase CitA.,Sevvana M, Vijayan V, Zweckstetter M, Reinelt S, Madden DR, Herbst-Irmer R, Sheldrick GM, Bott M, Griesinger C, Becker S J Mol Biol. 2008 Mar 21;377(2):512-23. Epub 2008 Jan 16. PMID:18258261[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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