title: Effect of propensity of hexagonal II phase formation on the activity of mitochondrial ubiquinol-cytochrome c reductase and H(+)-ATPase.
abstract: The propensity of hexagonal II phase formation plays an important role in the activity of mitochondrial ubiquinol-cytochrome c reductase or H(+)-ATPase. The respiratory control ratio of reconstituted ubiquinol-cytochrome c reductase or the ATP-induced membrane potential of reconstituted H(+)-ATPase became higher as the non-bilayer phospholipid phosphatidylethanolamine content of proteoliposomes increased. The highest respiratory control ratio or ATP-induced membrane potential was obtained in the case of 60-80% phosphatidylethanolamine-containing proteoliposomes. Dioleoylphosphatidylethanolamine could significantly enhance the respiratory control ratio of ubiquinol-cytochrome c reductase and ATP-induced membrane potential of H(+)-ATPase, while no obvious change could be observed when dielaidoylphosphatidylethanolamine was used. The bilayer to hexagonal II phase transition temperature of ubiquinol-cytochrome c reductase-containing proteoliposomes reconstituted with phosphatidylcholine+phosphatidylethanolamine increases with decreasing content of phosphatidylethanolamine. Several additives such as the bilayer stabilizers, cholesterol 3-sulfate and carbobenzoxy-D-Phe-L-PheGly, or hexagonal II phase-forming promoters, such as diolein or eicosane, can decrease or increase the activity of these two enzyme complexes.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: L X
authors.initials: LX
authors.lastname: Zheng
authors.forename: F Y
authors.initials: FY
authors.lastname: Yang
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002788:Cholesterol Esters / Q000494:pharmacology; D002942:Circular Dichroism; D014450:Electron Transport Complex III / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005470:Fluorometry; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008929:Mitochondria, Heart / Q000201:enzymology*; D010713:Phosphatidylcholines / Q000032:analysis / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000032:analysis / Q000737:chemistry; D011510:Proteolipids / Q000737:chemistry; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013552:Swine; D013696:Temperature
chemical_list: D002788:Cholesterol Esters; D008051:Lipid Bilayers; D008081:Liposomes; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D011510:Proteolipids; C020485:proteoliposomes; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D014450:Electron Transport Complex III; C007045:cholesteryl sulfate