This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the transport of calcium. In vivo, probably exports the calcium from the cytoplasm to the periplasm and the extracellular medium. ATP + Ca(2+)(in) + H2O = ADP + Ca(2+)(out) + H(+) + phosphate Inhibited by vanadate. Hypersensitive to osmotic stress. Mutant lacks ATP-dependent calcium transport. Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIA subfamily. Truncated N-terminus.