Energizing the plasmalemma of marine photosynthetic organisms: The role of primary active transport

John A. Raven, John Beardall

Research output: Contribution to journalReview ArticleResearchpeer-review

7 Citations (Scopus)

Abstract

Generation of ion electrochemical potential differences by primary active transport can involve energy inputs from light, from exergonic redox reactions and from exergonic ATP hydrolysis. These electrochemical potential differences are important for homoeostasis, for signalling, and for energizing nutrient influx. The three main ions involved are H+, Na+ (efflux) and Cl- (influx). In prokaryotes, fluxes of all three of these ions are energized by ion-pumping rhodopsins, with one archaeal rhodopsin pumping H+into the cells; among eukaryotes there is also an H+ influx rhodopsin in Acetabularia and (probably) H+ efflux in diatoms. Bacteriochlorophyll-based photoreactions export H+ from the cytosol in some anoxygenic photosynthetic bacteria, but chlorophyll-based photoreactions in marine cyanobacteria do not lead to export of H+. Exergonic redox reactions export H+ and Na+ in photosynthetic bacteria, and possibly H+ in eukaryotic algae. P-type H+- and/or Na+-ATPases occur in almost all of the photosynthetic marine organisms examined. P-type H+-efflux ATPases occur in charophycean marine algae and flowering plants whereas P-type Na+-ATPases predominate in other marine green algae and non-green algae, possibly with H+-ATPases in some cases. An F-type Cl--ATPase is known to occur in Acetabularia. Some assignments, on the basis of genomic evidence, of P-type ATPases to H+ or Na+ as the pumped ion are inconclusive.

Original languageEnglish
Pages (from-to)333-346
Number of pages14
JournalJournal of the Marine Biological Association of the United Kingdom
Volume100
Issue number3
DOIs
Publication statusPublished - May 2020

Keywords

  • Bacteriochlorophyll
  • Cl
  • F-type ATPases
  • H
  • ion-pumping rhodopsins
  • Na
  • P-type ATPases

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