potassium-transporting ATPase ATP-binding subunit, KdpB, a subunit of the prokaryotic high-affinity potassium uptake system KdpFABC; similar to Escherichia coli KdpB
KdpFABC is a prokaryotic high-affinity potassium uptake system. It is expressed under K(+) limiting conditions when the other potassium transport systems are not able to provide a sufficient flow of K(+) into the bacteria. The KdpB subunit represents the catalytic subunit performing ATP hydrolysis. KdpB is comprised of four domains: the transmembrane domain, the nucleotide-binding domain, the phosphorylation domain, and the actuator domain. 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.