title: Lipid-mediated Protein-protein Interactions Modulate Respiration-driven ATP Synthesis.
abstract: Energy conversion in biological systems is underpinned by membrane-bound proton transporters that generate and maintain a proton electrochemical gradient across the membrane which used, e.g. for generation of ATP by the ATP synthase. Here, we have co-reconstituted the proton pump cytochrome bo3 (ubiquinol oxidase) together with ATP synthase in liposomes and studied the effect of changing the lipid composition on the ATP synthesis activity driven by proton pumping. We found that for 100 nm liposomes, containing 5 of each proteins, the ATP synthesis rates decreased significantly with increasing fractions of DOPA, DOPE, DOPG or cardiolipin added to liposomes made of DOPC; with e.g. 5% DOPG, we observed an almost 50% decrease in the ATP synthesis rate. However, upon increasing the average distance between the proton pumps and ATP synthases, the ATP synthesis rate dropped and the lipid dependence of this activity vanished. The data indicate that protons are transferred along the membrane, between cytochrome bo3 and the ATP synthase, but only at sufficiently high protein densities. We also argue that the local protein density may be modulated by lipid-dependent changes in interactions between the two proteins complexes, which points to a mechanism by which the cell may regulate the overall activity of the respiratory chain.
authors.affiliation: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Tobias
authors.initials: T
authors.lastname: Nilsson
authors.affiliation: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Camilla Rydström
authors.initials: CR
authors.lastname: Lundin
authors.affiliation: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Gustav
authors.initials: G
authors.lastname: Nordlund
authors.affiliation: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Pia
authors.initials: P
authors.lastname: Ädelroth
authors.affiliation: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.|Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: von Ballmoos
authors.affiliation: Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Brzezinski
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D004734:Energy Metabolism; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism*; D008958:Models, Molecular; D010088:Oxidoreductases / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000737:chemistry / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D011522:Protons; D014451:Ubiquinone / Q000737:chemistry / Q000378:metabolism
chemical_list: D008081:Liposomes; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D011522:Protons; D014451:Ubiquinone; D000255:Adenosine Triphosphate; D010088:Oxidoreductases; C432586:ubiquinol oxidase; C474451:F1F0-ATP synthase; D025261:Mitochondrial Proton-Translocating ATPases; C017251:1,2-oleoylphosphatidylcholine