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Complex I function in mitochondrial supercomplexes.

Giorgio Lenaz1, Gaia Tioli1, Anna Ida Falasca2

  • 1Dipartimento di Scienze Biomediche e Neuromotorie, Alma Mater Studiorum, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy.

Biochimica Et Biophysica Acta
|January 29, 2016
PubMed
Summary

Mitochondrial supercomplexes facilitate electron transfer via channeled Coenzyme Q, not random diffusion. This assembly also regulates reactive oxygen species production by Complex I.

Keywords:
ChannellingComplex I (NADH:ubiquinone oxidoreductase)MitochondriaROSSupercomplex

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Area of Science:

  • Biochemistry
  • Mitochondrial biology
  • Cellular respiration

Background:

  • Mitochondrial Complex I is a key enzyme in cellular respiration.
  • Complex I exists within larger supercomplexes, including those with Complex III and Complex IV.
  • The precise mechanism of electron transfer between complexes is debated.

Purpose of the Study:

  • To review the functional properties of mitochondrial Complex I within supercomplexes.
  • To present evidence supporting electron channeling via bound Coenzyme Q for electron transfer.
  • To discuss the role of supercomplex assembly in regulating reactive oxygen species generation.

Main Methods:

  • Review of existing literature and experimental evidence.
  • Analysis of studies on mitochondrial supercomplex structure and function.
  • Integration of data on electron transfer mechanisms and reactive oxygen species production.

Main Results:

  • Evidence favors electron channeling through bound Coenzyme Q for electron transfer from Complex I to Complex III.
  • This contrasts with the diffusion hypothesis for Coenzyme Q.
  • Supercomplex assembly provides a mechanism for controlling reactive oxygen species generation by Complex I.

Conclusions:

  • Mitochondrial supercomplexes, particularly involving Complex I, III, and IV, are functionally significant.
  • Electron channeling via bound Coenzyme Q is a key feature of electron transfer within these supercomplexes.
  • Supercomplex formation plays a crucial role in regulating mitochondrial reactive oxygen species production.