An electron transfer flavoprotein (ETF) or electron transfer flavoprotein complex (CETF) is a
flavoprotein
Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin.
Flavoproteins are involved in a wide array of biological processes, including removal of radicals contributing to oxidative stress, photosynthesis, and DNA repair. T ...
located on the matrix face of the inner mitochondrial membrane and functions as a specific electron acceptor for primary
dehydrogenase
A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as ...
s, transferring the electrons to terminal respiratory systems such as
electron-transferring-flavoprotein dehydrogenase. They can be functionally classified into constitutive, "housekeeping" ETFs, mainly involved in the oxidation of fatty acids (Group I), and ETFs produced by some prokaryotes under specific growth conditions, receiving electrons only from the oxidation of specific substrates (Group II).
ETFs are heterodimeric proteins composed of an alpha and beta subunit (
ETFA and
ETFB), and contain an
FAD
A fad or trend is any form of collective behavior that develops within a culture, a generation or social group in which a group of people enthusiastically follow an impulse for a short period.
Fads are objects or behaviors that achieve short- ...
cofactor and
AMP.
ETF consists of three domains: domains I and II are formed by the N- and C-terminal portions of the alpha subunit, respectively, while domain III is formed by the beta subunit. Domains I and III share an almost identical alpha-beta-alpha sandwich fold, while domain II forms an alpha-beta-alpha sandwich similar to that of bacterial
flavodoxins. FAD is bound in a cleft between domains II and III, while domain III binds the AMP molecule. Interactions between domains I and III stabilise the protein, forming a shallow bowl where domain II resides.
Mutation in ETFs can lead to deficiency of passing reducing equivalent of FADH
2 to electron transport chain, causing
Glutaric acidemia type 2
See also
*
Electron transport chain
An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couple ...
*
Electron-transferring-flavoprotein dehydrogenase
*
Glutaric acidemia type 2
*
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...
*
Microbial metabolism
*
Oxidative phosphorylation
Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine t ...
References
{{reflist
External links
Pfam entry for Electron transfer flavoprotein domainPfam entry for Electron transfer flavoprotein FAD-binding domain
Proteins