Subunit composition of the H+-ATPase complex from anaerobic bacterium Lactobacillus casei

The H+-ATPase complex has been isolated from the membranes of the anaerobic bacterium Lactobacillus casei by two independent methods. 1. The crossed-immunoelectrophoresis of the 14C-labelled ATPase complex against antibodies to a highly purified soluble ATPase has been used. The subunit composition of the complex has been established by autoradiography. The soluble part of L. casei ATPase, in contrast to coupling factor F1-ATPases of aerobic bacteria, chloroplasts and mitochondria which include two kinds of large subunit (alpha and beta), consists of one kind of large subunit with a molecular mass of 43 kDa. Moreover, a minor polypeptide of 25 kDa has been found in the soluble ATPase. Factor F0 of L. casei ATPase complex consists of a 16-kDa subunit and two subunits with molecular masses less than 14 kDa. 2. A dicyclohexylcarbodiimide-sensitive ATPase complex has been isolated from L. casei membranes by treating them with a mixture of octyl glucoside and sodium cholate. The complex, purified by centrifugation on a sucrose density gradient, contains the main subunits with molecular masses of 43 kDa, 25 kDa and 16 kDa and a dicyclohexylcarbodiimide-binding subunit with a molecular mass less than 14 kDa.