Fungal respiration: a fusion of standard and alternative components

Biochim Biophys Acta. 2001 Apr 2;1504(2-3):179-95. doi: 10.1016/s0005-2728(00)00251-6.


In animals, electron transfer from NADH to molecular oxygen proceeds via large respiratory complexes in a linear respiratory chain. In contrast, most fungi utilise branched respiratory chains. These consist of alternative NADH dehydrogenases, which catalyse rotenone insensitive oxidation of matrix NADH or enable cytoplasmic NADH to be used directly. Many also contain an alternative oxidase that probably accepts electrons directly from ubiquinol. A few fungi lack Complex I. Although the alternative components are non-energy conserving, their organisation within the fungal electron transfer chain ensures that the transfer of electrons from NADH to molecular oxygen is generally coupled to proton translocation through at least one site. The alternative oxidase enables respiration to continue in the presence of inhibitors for ubiquinol:cytochrome c oxidoreductase and cytochrome c oxidase. This may be particularly important for fungal pathogens, since host defence mechanisms often involve nitric oxide, which, whilst being a potent inhibitor of cytochrome c oxidase, has no inhibitory effect on alternative oxidase. Alternative NADH dehydrogenases may avoid the active oxygen production associated with Complex I. The expression and activity regulation of alternative components responds to factors ranging from oxidative stress to the stage of fungal development.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Electron Transport Complex I
  • Electron Transport Complex II
  • Electron Transport Complex III / chemistry
  • Electron Transport Complex IV / chemistry
  • Electron Transport*
  • Fungi / chemistry
  • Fungi / genetics
  • Fungi / physiology*
  • Gene Expression Regulation
  • Mitochondrial Proteins
  • Models, Molecular
  • Molecular Sequence Data
  • Multienzyme Complexes / chemistry
  • NADH, NADPH Oxidoreductases / chemistry
  • NADH, NADPH Oxidoreductases / deficiency
  • Oxidoreductases / chemistry
  • Oxidoreductases / genetics
  • Plant Proteins
  • Plants / enzymology
  • Proton-Motive Force
  • Saccharomyces cerevisiae / enzymology
  • Sequence Alignment
  • Succinate Dehydrogenase / chemistry


  • Mitochondrial Proteins
  • Multienzyme Complexes
  • Plant Proteins
  • Oxidoreductases
  • alternative oxidase
  • Electron Transport Complex II
  • Succinate Dehydrogenase
  • NADH, NADPH Oxidoreductases
  • Electron Transport Complex IV
  • Electron Transport Complex I
  • Electron Transport Complex III