HepK, a protein-histidine kinase from the cyanobacterium Anabaena sp. strain PCC 7120, binds sequence-specifically to DNA

Introduction Two-component phosphorelay regulatory systems are widespread in prokaryotes, and are found also in fungi, amoebae and plants [1,2]. Typically, a sensory protein-histidine kinase phosphorylates its own conserved histidine residue in response to an environmental stimulus. Histidine kinases are not commonly known to function by binding to DNA, although they have