Solution NMR structure of yeast Rcf1, a protein involved in respiratory supercomplex formation

Proc Natl Acad Sci U S A. 2018 Mar 20;115(12):3048-3053. doi: 10.1073/pnas.1712061115. Epub 2018 Mar 5.


The Saccharomyces cerevisiae respiratory supercomplex factor 1 (Rcf1) protein is located in the mitochondrial inner membrane where it is involved in formation of supercomplexes composed of respiratory complexes III and IV. We report the solution structure of Rcf1, which forms a dimer in dodecylphosphocholine (DPC) micelles, where each monomer consists of a bundle of five transmembrane (TM) helices and a short flexible soluble helix (SH). Three TM helices are unusually charged and provide the dimerization interface consisting of 10 putative salt bridges, defining a "charge zipper" motif. The dimer structure is supported by molecular dynamics (MD) simulations in DPC, although the simulations show a more dynamic dimer interface than the NMR data. Furthermore, CD and NMR data indicate that Rcf1 undergoes a structural change when reconstituted in liposomes, which is supported by MD data, suggesting that the dimer structure is unstable in a planar membrane environment. Collectively, these data indicate a dynamic monomer-dimer equilibrium. Furthermore, the Rcf1 dimer interacts with cytochrome c, suggesting a role as an electron-transfer bridge between complexes III and IV. The Rcf1 structure will help in understanding its functional roles at a molecular level.

Keywords: bicelles; charge zipper; lipids; membrane proteins; mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Computer Simulation
  • Cytochromes c / chemistry
  • Cytochromes c / metabolism
  • Electron Transport Complex IV / chemistry*
  • Electron Transport Complex IV / metabolism
  • Escherichia coli / metabolism
  • Lipids / chemistry
  • Magnetic Resonance Spectroscopy
  • Models, Chemical
  • Models, Molecular
  • Protein Conformation
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / metabolism


  • Lipids
  • Rcf1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Cytochromes c
  • Electron Transport Complex IV

Associated data

  • PDB/5NF8