Reconstituted plant uncoupling mitochondrial protein allows for proton translocation via fatty acid cycling mechanism
Language English Country United States Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
9305881
DOI
10.1074/jbc.272.39.24272
PII: S0021-9258(19)63594-5
Knihovny.cz E-resources
- MeSH
- Biological Transport MeSH
- Ion Channels MeSH
- Kinetics MeSH
- Sulfonic Acids metabolism MeSH
- Fatty Acids metabolism MeSH
- Membrane Proteins metabolism MeSH
- Mitochondrial Proteins MeSH
- Proteolipids metabolism MeSH
- Protons MeSH
- Solanum lycopersicum metabolism MeSH
- Solanum tuberosum metabolism MeSH
- Carrier Proteins metabolism MeSH
- Uncoupling Protein 1 MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Ion Channels MeSH
- Sulfonic Acids MeSH
- Fatty Acids MeSH
- Membrane Proteins MeSH
- Mitochondrial Proteins MeSH
- Proteolipids MeSH
- proteoliposomes MeSH Browser
- Protons MeSH
- Carrier Proteins MeSH
- Uncoupling Protein 1 MeSH
Potato and tomato plant uncoupling mitochondrial protein (PUMP) was reconstituted into liposomes, and K+ or H+ fluxes associated with fatty acid (FA)-induced ion movement were measured using fluorescent ion indicators potassium binding benzofuraneisophthalate and 6-methoxy-N-(3-sulfopropyl)-quinolinium. We suggest that PUMP, like its mammalian counterpart, the uncoupling protein of brown adipose tissue mitochondria (Garlid, K. D., Orosz, D. E., Modrianský, M., Vassanelli, S., and Jeek, P. (1996), J. Biol. Chem. 271, 2615-2702), allows for H+ translocation via a FA cycling mechanism. Reconstituted PUMP translocated anionic linoleic and heptylbenzoic acids, undecanesulfonate, and hexanesulfonate, but not phenylvaleric and abscisic acids or Cl-. Transport was inhibited by ATP and GDP. Internal acidification of protein-free liposomes by linoleic or heptylbenzoic acid indicated that H+ translocation occurs by FA flip-flopping across the lipid bilayer. However, addition of valinomycin after FA-initiated GDP-sensitive H+ efflux solely in proteoliposomes, indicating that influx of anionic FA via PUMP precedes a return of protonated FA carrying H+. Phenylvaleric acid, unable to flip-flop, was without effect. Kinetics of FA and undecanesulfonate uniport suggested the existence of an internal anion binding site. Exponential flux-voltage characteristics were also studied. We suggest that regulated uncoupling in plant mitochondria may be important during fruit ripening, senescence, and seed dormancy.
References provided by Crossref.org
Channel character of uncoupling protein-mediated transport