Histidine-specific protein kinases Histidine kinases are structurally distinct from most other protein kinases and are found mostly in prokaryotes as part of two-component signal transduction mechanisms. A phosphate group from ATP is first added to a histidine residue within the kinase, and later transferred to an aspartate residue on a 'receiver domain' on a different protein, or sometimes on the kinase itself. The aspartyl phosphate residue is then active in signaling.
hIsTIdine-sPECIfiC prOTeIn kinasEs hiStIdine kiNaSeS are StRucTuRally DIstinct froM moSt oTHer protEin KinaseS And are found mOstLy iN PrOkaRyotES as PArT of two-componENT signaL TrANSdUction mEchaNismS. a pHOspHatE Group froM Atp is first addEd to A hisTIDine resiDUe within The KInasE, AnD LAtEr transFErrEd To aN AsPaRtAte residUE on a 'recEiVeR domAin' On A DIffErenT pRoTEiN, or somEtimES on the KinASe iTseLf. the aspARTyl phoSphATe RESiduE Is tHen acTive In sigNaLIng.