Supramolecular structure of the OXPHOS system in highly thermogenic tissue of Arum maculatum
Creators: name: Sunderhaus, Stephanie
name: Klodmann, Jennifer
name: Lenz, Christof
name: Braun, Hans-Peter
Publisher: name: Amsterdam [u.a.] : Elsevier Science
Year: 2010
Subjects: subject: Alternative oxidase
subject: Arum maculatum
subject: Mitochondria
subject: Oxidative phosphorylation
subject: Respiratory supercomplexes
subject: Thermogenesis
subject: alternative oxidase
subject: cytochrome c oxidase
subject: multienzyme complex
subject: oxidoreductase
subject: reduced nicotinamide adenine dinucleotide dehydrogenase (ubiquinone)
subject: ubiquinol cytochrome c reductase
subject: vegetable protein
subject: article
subject: Arum
subject: chemistry
subject: electron transport
subject: metabolism
subject: mitochondrion
subject: oxidative phosphorylation
subject: Electron Transport
subject: Electron Transport Complex I
subject: Electron Transport Complex III
subject: Electron Transport Complex IV
subject: Multienzyme Complexes
subject: Oxidative Phosphorylation
subject: Oxidoreductases
subject: Plant Proteins
subject: Arabidopsis
subject: Arabidopsis thaliana
subject: Iva
subject: Dewey Decimal Classification::600 | Technik::630 | Landwirtschaft, Veterinärmedizin
subject: Dewey Decimal Classification::600 | Technik::640 | Hauswirtschaft und Familienleben
subject: Dewey Decimal Classification::500 | Naturwissenschaften::580 | Pflanzen (Botanik)

description: The protein complexes of the mitochondrial respiratory chain associate in defined ways forming supramolecular structures called respiratory supercomplexes or respirasomes. In plants, additional oxidoreductases participate in respiratory electron transport, e.g. the so-called "alternative NAD(P)H dehydrogenases" or an extra terminal oxidase called "alternative oxidase" (AOX). These additional enzymes were previously reported not to form part of respiratory supercomplexes. However, formation of respiratory supercomplexes might indirectly affect "alternative respiration" because electrons can be channeled within the supercomplexes which reduces access of the alternative enzymes towards their electron donating substrates. Here we report an investigation on the supramolecular organization of the respiratory chain in thermogenic Arum maculatum appendix mitochondria, which are known to have a highly active AOX for heat production. Investigations based on mild membrane solubilization by digitonin and protein separation by blue native PAGE revealed a very special organization of the respiratory chain in A. maculatum, which strikingly differs to the one described for the model plant Arabidopsis thaliana: (i) complex I is not present in monomeric form but exclusively forms part of a I + III2 supercomplex, (ii) the III2 + IV and I + III2 + IV supercomplexes are detectable but of low abundance, (iii) complex II has fewer subunits than in A. thaliana, and (iv) complex IV is mainly present as a monomer in a larger form termed "complex IVa". Since thermogenic tissue of A. maculatum at the same time has high AOX and I + III2 supercomplex abundance and activity, negative regulation of the alternative oxidase by supercomplex formation seems not to occur. Functional implications are discussed. © 2010 Elsevier Masson SAS. All rights reserved.