Primary Structure of the α-Subunit of Human Na, K-ATPase Deduced from cDNA Sequence1

Abstract

Clones carrying cDNA sequences for the α-subunit of the Na, K-ATPase from HeLa cells have been isolated. Nucleotide sequence analysis of the cloned cDNA has revealed the primary structure of this polypeptide, which consists of 1,023 amino acids. The a-subunit of the human Na, K-ATPase exhibited 87% homology with its Torpedo counterpart and 98% homology with its sheep counterpart. The six putative transmembrane segments M1-M6 showed higher conservation than the total segments. Total genomic Southern hybridization indicated the existence of at most two copies, possibly only one, of the gene encoding the Na, K-ATPase a-subunit in the human genome.