Regulatory role of the respiratory supercomplex factors in Saccharomyces cerevisiae

Rydström Lundin, Camilla; von Ballmoos, Christoph; Ott, Martin; Ädelroth, Pia; Brzezinski, Peter (2016). Regulatory role of the respiratory supercomplex factors in Saccharomyces cerevisiae. Proceedings of the National Academy of Sciences of the United States of America - PNAS, 113(31), E4476-E4485. National Academy of Sciences NAS 10.1073/pnas.1601196113

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The respiratory supercomplex factors (Rcf) 1 and 2 mediate supramolecular interactions between mitochondrial complexes III (ubiquinol-cytochrome c reductase; cyt. bc1) and IV (cytochrome c oxidase; CytcO). In addition, removal of these polypeptides results in decreased activity of CytcO, but not of cyt. bc1 In the present study, we have investigated the kinetics of ligand binding, the single-turnover reaction of CytcO with O2, and the linked cyt. bc1-CytcO quinol oxidation-oxygen-reduction activities in mitochondria in which Rcf1 or Rcf2 were removed genetically (strains rcf1Δ and rcf2Δ, respectively). The data show that in the rcf1Δ and rcf2Δ strains, in a significant fraction of the population, ligand binding occurs over a time scale that is ∼100-fold faster (τ ≅ 100 μs) than observed with the wild-type mitochondria (τ ≅ 10 ms), indicating structural changes. This effect is specific to removal of Rcf and not dissociation of the cyt. bc1-CytcO supercomplex. Furthermore, in the rcf1Δ and rcf2Δ strains, the single-turnover reaction of CytcO with O2 was incomplete. This observation indicates that the lower activity of CytcO is caused by a fraction of inactive CytcO rather than decreased CytcO activity of the entire population. Furthermore, the data suggest that the Rcf1 polypeptide mediates formation of an electron-transfer bridge from cyt. bc1 to CytcO via a tightly bound cyt. c We discuss the significance of the proposed regulatory mechanism of Rcf1 and Rcf2 in the context of supramolecular interactions between cyt. bc1 and CytcO.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

von Ballmoos, Christoph

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

0027-8424

Publisher:

National Academy of Sciences NAS

Language:

English

Submitter:

Christoph von Ballmoos

Date Deposited:

29 Nov 2017 14:59

Last Modified:

29 Nov 2017 14:59

Publisher DOI:

10.1073/pnas.1601196113

BORIS DOI:

10.7892/boris.106341

URI:

https://boris.unibe.ch/id/eprint/106341

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