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| Subject Categories:
Signal Transduction
| Structural Biology
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The EMBO Journal
(2005) 24, 4247–4259, doi:10.1038/sj.emboj.7600886 Published online 1 December 2005
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| Structure of the entire cytoplasmic portion of a sensor histidine-kinase protein |
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Alberto Marina1, 2, Carey D Waldburger3, 4 and Wayne A Hendrickson1
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1 Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
2 Macromolecular Crystallography Unit, Instituto de Biomedicina de Valencia (CSIC), Valencia, Spain
3 Department of Microbiology, Columbia University, New York, NY, USA
To whom correspondence should be addressed
Wayne A Hendrickson, Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA. Tel.: +1 212 305 3456; Fax: +1 212 305 7379; E-mail: wayne@convex.hhmi.columbia.edu
4 Present address: Department of Biology, William Paterson University, Wayne, NJ 07474, USA
Received 6 May 2005; Accepted 3 November 2005; Published online 1 December 2005.
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| Abstract |
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The large majority of histidine kinases (HKs) are multifunctional enzymes having autokinase, phosphotransfer and phosphatase activities, and most of these are transmembrane sensor proteins. Sensor HKs possess conserved cytoplasmic phosphorylation and ATP-binding kinase domains. The different enzymatic activities require participation by one or both of these domains, implying the need for different conformational states. The catalytic domains are linked to the membrane through a coiled-coil segment that sometimes includes other domains. We describe here the first crystal structure of the complete cytoplasmic region of a sensor HK, one from the thermophile Thermotoga maritima in complex with ADP N at 1.9 Å resolution. The structure reveals previously unidentified functions for several conserved residues and reveals the relative disposition of domains in a state seemingly poised for phosphotransfer. The structure thereby inspires hypotheses for the mechanisms of autophosphorylation, phosphotransfer and response-regulator dephosphorylation, and for signal transduction through the coiled-coil segment. Mutational tests support the functional relevance of interdomain contacts. |
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| Keywords: crystal structure, PhoQ, phosphotransfer, selenomethionyl MAD, two-component systems |
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