plant and fungal plasma membrane H(+)-ATPases, and related bacterial and archaeal putative H(+)-ATPases
This subfamily includes eukaryotic plasma membrane H(+)-ATPase which transports H(+) from the cytosol to the extracellular space, thus energizing the plasma membrane for the uptake of ions and nutrients, and is expressed in plants and fungi. This H(+)-ATPase consists of four domains: a transmembrane domain and three cytosolic domains: nucleotide-binding domain, phosphorylation domain and actuator domain, and belongs to the P-type ATPase type III subfamily. This subfamily also includes the putative P-type H(+)-ATPase, MJ1226p of the anaerobic hyperthermophilic archaea Methanococcus jannaschii. The P-type ATPases, are a large family of integral membrane transporters that are of critical importance in all kingdoms of life. They generate and maintain (electro-) chemical gradients across cellular membranes, by translocating cations, heavy metals and lipids, and are distinguished from other main classes of transport ATPases (F- , V- , and ABC- type) by the formation of a phosphorylated (P-) intermediate state in the catalytic cycle.