The branched mitochondrial respiratory chain from Debaryomyces hansenii: Components and supramolecular organization

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• 作者：Alfredo Cabrera-Orefice ; Natalia Chiquete-F茅lix ; Juan Espinasa-Jaramillo ; M贸nica Rosas-Lemus ; Sergio Guerrero-Castillo ; Antonio Pe帽a ; Salvador Uribe-Carvajal
• 关键词：ADP ; adenosine diphosphate ; AMP ; adenosine monophosphate ; AOX ; alternative oxidase ; BN ; blue-native ; COX ; cytochrome c oxidase ; CRR ; cyanide-resistant respiration ; Dig ; digitonin ; IMM ; inner mitochondrial membrane ; LC-MS ; liquid chromatography mass spectrometry ; LM ; laurylmaltoside ; MitGPDH ; glycerol-phosphate dehydrogenase (mitochondrial isoform) ; MUC ; mitochondrial unspecific channel ; MW ; molecular weight ; NDH ; NADH dehydrogenase activity ; NDH2e ; alternative external NADH dehydrogenase ; PAGE
• 刊名：Biochimica et Biophysica Acta (BBA)/Bioenergetics
• 出版年：January, 2014
• 年：2014
• 卷：1837
• 期：1
• 页码：73-84
• 全文大小：1239 K

文摘

The branched respiratory chain in mitochondria from the halotolerant yeast Debaryomyces hansenii contains the classical complexes I, II, III and IV plus a cyanide-insensitive, AMP-activated, alternative-oxidase (AOX). Two additional alternative oxidoreductases were found in this organism: an alternative NADH dehydrogenase (NDH2e) and a mitochondrial isoform of glycerol-phosphate dehydrogenase (_MitGPDH). These monomeric enzymes lack proton pump activity. They are located on the outer face of the inner mitochondrial membrane. NDH2e oxidizes exogenous NADH in a rotenone-insensitive, flavone-sensitive, process. AOX seems to be constitutive; nonetheless, most electrons are transferred to the cytochromic pathway. Respiratory supercomplexes containing complexes I, III and IV in different stoichiometries were detected. Dimeric complex V was also detected. In-gel activity of NADH dehydrogenase, mass spectrometry, and cytochrome c oxidase and ATPase activities led to determine the composition of the putative supercomplexes. Molecular weights were estimated by comparison with those from the yeast Y. lipolytica and they were IV₂, I-IV, III₂-IV₄, V₂, I-III₂, I-III₂-IV, I-III₂-IV₂, I-III₂-IV₃ and I-III₂-IV₄. Binding of the alternative enzymes to supercomplexes was not detected. This is the first report on the structure and organization of the mitochondrial respiratory chain from D. hansenii.