Soluble P-type ATPase from an archaeon, Methanococcus jannaschii

MJ0968 has been proposed to be an ancestor of P-type ATPase, because its pr imary structure is highly homologous to that of the core catalytic domain o f P-type ATPase, However it completely lacks amino acid sequences that poss ibly constitute transmembrane domains. To examine if MJ0968 is indeed a P-t ype ATPase, it was overexpressed in Escherichia coli and purified. It did s how ATPase activity, autophosphorylation and inhibition by vanadate, All th ese properties support the idea that MJ0968 is indeed a soluble P-type ATPa se. (C) 2000 Federation of European Biochemical Societies.