Related Experiment Video
Updated: May 7, 2026
05:27
Inner Mitochondrial Membrane Sensitivity to Na+ Reveals Partially Segmented Functional CoQ Pools
Published on: July 20, 2022
The alternative oxidases: simple oxidoreductase proteins with complex functions
Luke Young1, Tomoo Shiba, Shigeharu Harada
1*Department of Biochemistry and Molecular Biology, School of Life Sciences, University of Sussex, Brighton BN1 9QG, U.K.
Biochemical Society Transactions
|September 25, 2013
Summary
Alternative oxidases, crucial electron transport proteins in plants and parasites like Trypanosoma brucei, reduce oxygen to water. Their structure and function are compared to other di-iron proteins, proposing a novel oxygen reduction mechanism.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Alternative oxidases are essential membrane-bound proteins in plants, fungi, and parasites.
- These proteins play a vital role in cellular respiration by reducing oxygen to water.
- Trypanosoma brucei, a parasite causing trypanosomiasis, possesses a significant alternative oxidase.
Purpose of the Study:
- To compare the ligation spheres of alternative oxidases with other di-iron carboxylate proteins.
- To elucidate the structural features of the trypanosomal alternative oxidase.
- To propose a mechanism for oxygen reduction by alternative oxidases.
Main Methods:
- Structural analysis of the trypanosomal alternative oxidase at 2.85 Å resolution.
- Comparative analysis of primary and secondary ligation spheres.
- Bioinformatic and biochemical comparisons with related di-iron proteins.
Main Results:
- The crystal structure revealed key functional features of the trypanosomal alternative oxidase.
- Significant similarities and differences were identified in the ligation spheres.
- A proposed mechanism for the four-electron reduction of oxygen to water was developed.
Conclusions:
- Alternative oxidases share conserved structural motifs with other di-iron carboxylate proteins.
- Structural insights facilitate understanding of the oxygen reduction mechanism.
- This review provides a framework for further investigation into alternative oxidase function and inhibition.
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
Related Concept Videos
01:41The Supercomplexes in the Crista Membrane
The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through respiratory complexes I to V. These complexes have been widely studied for decades, and it has been proven that they form supramolecular structures called respiratory supercomplexes (SC). These higher-order complexes may be crucial in maintaining the biochemical structure and improving the physiological activity of the individual complexes while...
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
01:46Electron Transport Chain: Complex I and II
The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
ROS generation is regulated and maintained at moderate levels necessary...
01:27Redox Reactions
Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
01:24Redox Reactions
Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...
01:19Oxidation and Reduction of Organic Molecules
Energy production within a cell involves many coordinated chemical pathways. Most of these pathways are combinations of oxidation and reduction reactions, which occur at the same time. An oxidation reaction strips an electron from an atom in a compound, and the addition of this electron to another compound is a reduction reaction. Because oxidation and reduction usually occur together, these pairs of reactions are called redox reactions.
The removal of an electron from a molecule, results in a...
The removal of an electron from a molecule, results in a...