The mitochondrial cyanide-resistant oxidase: structural conservation amid regulatory diversity.

Journal Article (Review;Journal Article)

Mitochondria from all plants, many fungi and some protozoa contain a cyanide-resistant, alternative oxidase that functions in parallel with cytochrome c oxidase as the terminal oxidase on the electron transfer chain. Characterization of the structural and potential regulatory features of the alternative oxidase has advanced considerably in recent years. The active site is proposed to contain a di-iron center belonging to the ribonucleotide reductase R2 family and modeling of a four-helix bundle to accommodate this active site within the C-terminal two-thirds of the protein has been carried out. The structural features of this active site are conserved among all known alternative oxidases. The post-translational regulatory features of the alternative oxidase are more variable among organisms. The plant oxidase is dimeric and can be stimulated by either alpha-keto acids or succinate, depending upon the presence or absence, respectively, of a critical cysteine residue found in a conserved block of amino acids in the N-terminal region of the plant protein. The fungal and protozoan alternative oxidases generally exist as monomers and are not subject to organic acid stimulation but can be stimulated by purine nucleotides. The origins of these diverse regulatory features remain unknown but are correlated with sequence differences in the N-terminal third of the protein.

Full Text

Duke Authors

Cited Authors

  • Siedow, JN; Umbach, AL

Published Date

  • August 2000

Published In

Volume / Issue

  • 1459 / 2-3

Start / End Page

  • 432 - 439

PubMed ID

  • 11004460

Electronic International Standard Serial Number (EISSN)

  • 1878-2434

International Standard Serial Number (ISSN)

  • 0006-3002

Digital Object Identifier (DOI)

  • 10.1016/s0005-2728(00)00181-x


  • eng