Construction and Expression of Chimeric cDNAs of Na⁺/K⁺ and H⁺/K⁺-ATPase β-subunits

Abstract

Na⁺/K⁺- ATPase and H⁺/K⁺-ATPase consist of a catalytic α-subunit and a glycosylated β -subunit. Both β-subunits have similar structural features — they span the membrane once, leaving a short N-terminal portion in the cytoplasmic side, and a large portion including C-terminus outside of the cell where there are three highly conserved disulfide bridges(for a review, see ref.1). H⁺/K⁺-ATPase β-subunit forms a stable assembly with Na⁺/K⁺-ATPase α-subunit, but the resulting aβ complex is not functional, at least in ATPase activity(5). Construction of chimeras between Na⁺/K⁺- and H⁺/K⁺-ATPase β-subunit, and the expression of the chimeras with Na⁺/K⁺ -ATPase α-subunit in Xenopus oocytes should allow us to determine which regions of Na⁺/K⁺-ATPase β-subunit are required for the expression of functional αβ complex.