2c2a: Difference between revisions

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 ADPbetaN at 1.9 A, 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.

2C2A is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with SO4 and ADP as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2C2A OCA].  

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