Characterization of a plasma membrane H+-ATPase from the extremely acidophilic alga Dunaliella acidophila

Israel Sekler, Heinz Ulrich Gläser, Uri Pick

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Dunaliella acidophila is an unicellular green alga which grows optimally at pH 0-1 while maintaining neutral internal pH. A plasma membrane preparation of this algae has been purified on sucrose density gradients. The preparation exhibits vanadatesensitive ATPase activity of 2 μmol Pi/mg protein/min, an activity 15 to 30-fold higher than that in the related neutrophilic species D. salina. The following properties suggest that the ATPase is an electrogenic plasma membrane H+ pump. (i) ATP induces proton uptake and generates a positive-inside membrane potential as demonstrated with optical probes. (ii) ATP hydrolysis and proton uptake are inhibited by vanadate, diethylstilbestrol, dicyclohexylcarbodiimide and erythrosine but not by molybdate, azide or nitrate. (iii) ATP hydrolysis and proton uptake are stimulated by fussicoccin in a pH-dependent manner as found for plants plasma membrane H+-ATPase. Unusual properties of this enzyme are: (i) the Km for ATP is around 60 μM, considerably lower than in other plasma membrane H+-ATPases, and (ii) the ATPase activity and proton uptake are stimulated three to fourfold by K+ and to a smaller extent by other monovalent cations. These results suggest that D. acidophila possesses a vanadate-sensitive H+-ATPase with unusual features enabling it to maintain the large transmembrane pH gradient.

Original languageEnglish
Pages (from-to)51-57
Number of pages7
JournalJournal of Membrane Biology
Volume121
Issue number1
DOIs
StatePublished - 1 Apr 1991
Externally publishedYes

Keywords

  • ATPase
  • H
  • acidophile
  • fusicoccin
  • plasma membrane

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

Fingerprint

Dive into the research topics of 'Characterization of a plasma membrane H+-ATPase from the extremely acidophilic alga Dunaliella acidophila'. Together they form a unique fingerprint.

Cite this