Supercomplex-associated Cox26 protein binds to cytochrome c oxidase.
Here we identified a hydrophobic 6.4kDa protein, Cox26, as a novel component of yeast mitochondrial supercomplex comprising respiratory complexes III and IV. Multi-dimensional native and denaturing electrophoretic techniques were used to identify proteins interacting with Cox26. The majority of the Cox26 protein was found non-covalently bound to the complex IV moiety of the III-IV supercomplexes. A population of Cox26 was observed to exist in a disulfide bond partnership with the Cox2 subunit of complex IV. No pronounced growth phenotype for Cox26 deficiency was observed, indicating that Cox26 may not play a critical role in the COX enzymology, and we speculate that Cox26 may serve to regulate or support the Cox2 protein. Respiratory supercomplexes are assembled in the absence of the Cox26 protein, however their pattern slightly differs to the wild type III-IV supercomplex appearance. The catalytic activities of complexes III and IV were observed to be normal and respiration was comparable to wild type as long as cells were cultivated under normal growth conditions. Stress conditions, such as elevated temperatures resulted in mild decrease of respiration in non-fermentative media when the Cox26 protein was absent.
Molekulare Bioenergetik, Zentrum der Biologischen Chemie, Cluster of Excellence Frankfurt Macromolecular Complexes Goethe-Universität Frankfurt, D-60590 Frankfurt, Germany; Functional Proteomics, Institute of Biochemistry I, Faculty of Medicine, Goethe-University of Frankfurt, D-60590 Frankfurt, Germany.
Valentina
V
Strecker
Molekulare Bioenergetik, Zentrum der Biologischen Chemie, Cluster of Excellence Frankfurt Macromolecular Complexes Goethe-Universität Frankfurt, D-60590 Frankfurt, Germany.
Zibirnisa
Z
Kadeer
Functional Proteomics, Institute of Biochemistry I, Faculty of Medicine, Goethe-University of Frankfurt, D-60590 Frankfurt, Germany.
Juliana
J
Heidler
Fakultät Angewandte Naturwissenschaften, Hochschule Esslingen, University of Applied Sciences, D-73728 Esslingen, Germany.
Cristina-Maria
CM
Cruciat
Molekulare Bioenergetik, Zentrum der Biologischen Chemie, Cluster of Excellence Frankfurt Macromolecular Complexes Goethe-Universität Frankfurt, D-60590 Frankfurt, Germany; Structural Bioenergetics Group, Institute of Biochemistry II, Medical School, Goethe University of Frankfurt, Germany.
Heike
H
Angerer
Molecular Bioinformatics, Institute of Computer Science, Johann Wolfgang Goethe-University, D-60325 Frankfurt am Main, Germany.
Heiko
H
Giese
Department of Functional Proteomics, Medizinisches Proteom-Center, Ruhr-Universität Bochum, D-44801 Bochum, Germany.
Kathy
K
Pfeiffer
Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA.
Rosemary A
RA
Stuart
Molekulare Bioenergetik, Zentrum der Biologischen Chemie, Cluster of Excellence Frankfurt Macromolecular Complexes Goethe-Universität Frankfurt, D-60590 Frankfurt, Germany; Functional Proteomics, Institute of Biochemistry I, Faculty of Medicine, Goethe-University of Frankfurt, D-60590 Frankfurt, Germany. Electronic address: wittig@med.uni-frankfurt.de.
Ilka
I
Wittig
D002384:Catalysis; D004220:Disulfides / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004586:Electrophoresis; D004795:Enzyme Stability; D057927:Hydrophobic and Hydrophilic Interactions; D008928:Mitochondria / Q000201:enzymology*; D051336:Mitochondrial Membranes / Q000201:enzymology*; D008958:Models, Molecular; D008970:Molecular Weight; D010101:Oxygen Consumption; D011485:Protein Binding; D011489:Protein Denaturation; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
C000610448:Cox26 protein, S cerevisiae; D004220:Disulfides; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV
Blue native electrophoresis; Cytochrome c oxidase; III–IV supercomplexes; Protein composition; Respiratory supercomplexes; Saccharomyces cerevisiae