This is the dimerisation and phosphoacceptor domain of asub-family of histidine kinases. It shares sequence similaritywith Pfam:PF00512 and Pfam:PF07536. It is usually found adjacentto a C-terminal ATPase domain (Pfam:PF02518). This domain isfound in a wide range of Bacteria and also several Archaea. Histidine kinase HisKA_2