Molecular cloning and characterization of Na,K-ATPase from Hydra vulgaris: implications for enzyme evolution and ouabain sensitivity.

Victor Canfield, K. Y. Xu, T. D'Aquila, A. W. Shyjan, Robert Levenson

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

We have used molecular and biochemical techniques to analyze Na,K-ATPase from a simple metazoan, Hydra vulgaris. First we isolated and characterized cDNA clones encoding the Na,K-ATPase alpha subunit from a Hydra lambda gt11 cDNA library. The open reading frame predicts a protein of 1031 amino acids that bears a high degree of primary sequence and secondary structure similarity to mammalian, avian, and arthropod alpha subunits. The predicted Hydra alpha subunit contains charged residues at the termini of the H1-H2 extracellular domain, suggesting that the Hydra alpha subunit may be resistant to cardiac glycoside inhibition. Biochemical analysis of partially purified Hydra Na,K-ATPase reveals both high- and low-affinity components of ouabain-inhibitable ATPase activity. Our results suggest that the evolutionary ancestor of all metazoans possessed a Na,K-ATPase alpha subunit that was highly conserved with respect to its vertebrate counterparts. Further, expression of a ouabain-resistant Na,K-ATPase activity in Hydra suggests that cardiac glycoside resistance arose randomly during evolution of the Na,K-ATPase.

Original languageEnglish (US)
Pages (from-to)339-348
Number of pages10
JournalThe New biologist
Volume4
Issue number4
StatePublished - Apr 1992

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)

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