Primary structure of the α-subunit of Torpedo californica (Na+ + K+)ATPase deduced from cDNA sequence

Abstract

Sodium- and potassium-dependent ATPase [(Na+ + K+)ATPase], which is responsible for the active transport of Na+ and K+, is distributed universally among animal cell membranes and consists of two types of subunits, alpha and beta (refs 1-4). The larger alpha-subunit with a relative molecular mass (Mr) of 84,000-120,000 is thought to have the catalytic role. We have now cloned and sequenced DNA complementary to the Torpedo californica electroplax messenger RNA encoding the alpha-subunit of (Na+ + K+)ATPase and have deduced the complete amino-acid sequence of the polypeptide. Some structural features of the alpha-subunit molecule related to the function of this active-transport protein are discussed.

Functional Properties of Na,K-ATPase, and Their Structural Implications, as Detected with Biophysical Techniques

“…The genes for the Na,KATPase have been cloned, including isoforms expressed in a variety of different tissues [51,59,71,83]. For the ␣-subunit, consisting of about 1,000 residues, a variety of experimental techniques [9,26,44,46,58,82] have demonstrated the existence of 10 transmembrane segments [45], with both N-and C-termini cytoplasmic.…”

Pig kidney Na+,K+‐ATPase

“…Comparison of the sequences of the catalytic subunits of Na+,K+-ATPase from ray electroplax [43], pig [14] and sheep [44] kidneys revealed an exceptionally high degree of homology (-90% even for diverse species). These polypeptides have rather extended regions of the sequences similar to those of other ion pumps earcoplasmic reticulum Ca'+-ATPase [38] and E. coli K+-ATPase [45]).…”

Family of human Na+,K+‐ATPase genes Structure of the gene for the catalytic subunit (αIII‐form) and its relationship with structural features of the protein

“…At present, the structures of several animal iontransporting ATPases of the E~E2 typeNa+,K+-ATPases [1,3,7,9,16,19,23,24], H+,K +-ATPase [25], and Ca2+-ATPases [26] -are defined by analysis of cDNA nucleotide sequences. Comparison of the known primary structures including that described above revealed several structural regions highly conservative among all these related enzymes.…”