1. Subunit–subunit interactions and overall topology of the dimeric mitochondrial ATP synthase of Polytomella sp
- Author
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Alexa Villavicencio-Queijeiro, Héctor Miranda-Astudillo, Francisco Figueroa-Martínez, Marie Lapaille, Stephan Wilkens, Diego González-Halphen, Miriam Vázquez-Acevedo, Julio A. Mignaco, Araceli Cano-Estrada, Debora Foguel, Yraima Cordeiro, Claire Remacle, and Pierre Cardol
- Subjects
Protein subunit ,Dimeric mitochondrial complex V ,Biophysics ,Chlorophycean algae ,Chlamydomonas reinhardtii ,Oxidative phosphorylation ,Topology ,Mitochondrial Proton-Translocating ATPases ,Biochemistry ,Chlorophyta ,ATP synthase gamma subunit ,Scattering, Radiation ,F1F0-ATP synthase ,Polytomella sp ,chemistry.chemical_classification ,biology ,ATP synthase ,Polytomella ,Cell Biology ,biology.organism_classification ,Stator stalk ,ASA subunits ,Microscopy, Electron ,Protein Subunits ,Enzyme ,chemistry ,biology.protein ,Protein Multimerization - Abstract
Mitochondrial F1F0-ATP synthase of chlorophycean algae is a dimeric complex of 1600kDa constituted by 17 different subunits with varying stoichiometries, 8 of them conserved in all eukaryotes and 9 that seem to be unique to the algal lineage (subunits ASA1–9). Two different models proposing the topological assemblage of the nine ASA subunits in the ATP synthase of the colorless alga Polytomella sp. have been put forward. Here, we readdressed the overall topology of the enzyme with different experimental approaches: detection of close vicinities between subunits based on cross-linking experiments and dissociation of the enzyme into subcomplexes, inference of subunit stoichiometry based on cysteine residue labelling, and general three-dimensional structural features of the complex as obtained from small-angle X-ray scattering and electron microscopy image reconstruction. Based on the available data, we refine the topological arrangement of the subunits that constitute the mitochondrial ATP synthase of Polytomella sp.
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