Cytochrome C1
Encyclopedia
Cytochrome C1 is formed in the cytosol
and targeted
to the mitochondrial intermembrane space. It is one of the constituents of complex III
, which forms the third proton pump in the mitochondrial electron transport chain
.
Cytochrome c1 is a subunit of the electron transport chain
protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex), which consists of the products of one mitochondrially encoded gene, MTCYTB (mitochondrial cytochrome b
) and ten nuclear genes: UQCRC1
, UQCRC2
, Cytochrome c1, UQCRFS1
(Rieske protein
), UQCRB
, UQCRQ http://www.ncbi.nlm.nih.gov/nuccore/98986462("11kDa protein"), UQCRH
(cyt c1 Hinge protein), Rieske Protein presequence, "cyt. c1 associated protein", and UQCR http://www.ncbi.nlm.nih.gov/nucleotide/19923785("Rieske-associated protein").
Ubiquinol:ferricytochrome c oxidoreductase is found in mitochondria, photosynthetic bacteria
and other prokaryotes. The general function of the complex
is electron
transfer between two mobile redox
carriers, ubiquinol
and cytochrome c
; the electron transfer is coupled with proton
translocation across the membrane, thus generating proton-motive force in the form of an electrochemical potential that can drive ATP
synthesis. In its structure and functions, the cytochrome bc1 complex bears extensive analogy to the cytochrome b6f
complex of chloroplast
s and cyanobacteria; cyt c1 plays an analogous role to cytochrome f, in spite of their different structures.
Cytosol
The cytosol or intracellular fluid is the liquid found inside cells, that is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into compartments....
and targeted
Protein targeting
Protein targeting or protein sorting is the mechanism by which a cell transports proteins to the appropriate positions in the cell or outside of it. Sorting targets can be the inner space of an organelle, any of several interior membranes, the cell's outer membrane, or its exterior via secretion...
to the mitochondrial intermembrane space. It is one of the constituents of complex III
Coenzyme Q - cytochrome c reductase
In enzymology, a ubiquinol—cytochrome-c reductase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are dihydroquinone and ferri- cytochrome c, whereas its 3 products are quinone , ferro- cytochrome c, and H+.This enzyme belongs to the family of...
, which forms the third proton pump in the mitochondrial electron transport chain
Electron transport chain
An electron transport chain couples electron transfer between an electron donor and an electron acceptor with the transfer of H+ ions across a membrane. The resulting electrochemical proton gradient is used to generate chemical energy in the form of adenosine triphosphate...
.
Cytochrome c1 is a subunit of the electron transport chain
Electron transport chain
An electron transport chain couples electron transfer between an electron donor and an electron acceptor with the transfer of H+ ions across a membrane. The resulting electrochemical proton gradient is used to generate chemical energy in the form of adenosine triphosphate...
protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex), which consists of the products of one mitochondrially encoded gene, MTCYTB (mitochondrial cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
) and ten nuclear genes: UQCRC1
UQCRC1
Cytochrome b-c1 complex subunit 1, mitochondrial is a protein that in humans is encoded by the UQCRC1 gene.Its gene product is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase , which consists of the products of one mitochondrially encoded gene, MTCYTB and ten nuclear...
, UQCRC2
UQCRC2
Cytochrome b-c1 complex subunit 2, mitochondrial is a protein that in humans is encoded by the UQCRC2 gene.Its gene product is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase , which consists of the products of one mitochondrially encoded gene, MTCYTB and ten nuclear...
, Cytochrome c1, UQCRFS1
UQCRFS1
Ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, also known as UQCRFS1, is a protein which in humans is encoded by the UQCRFS1 gene....
(Rieske protein
Rieske protein
Rieske proteins are iron-sulfur protein components of cytochrome bc1 complexes and cytochrome b6f complexes which were first discovered and isolated by John S. Rieske and co-workers in 1964. It is a unique [2Fe-2S] cluster in that one of the two Fe atoms is coordinated by two histidine residues...
), UQCRB
UQCRB
Ubiquinol-cytochrome c reductase binding protein, also known as UQCRB, is a protein which in humans is encoded by the UQCRB gene.- Function :...
, UQCRQ http://www.ncbi.nlm.nih.gov/nuccore/98986462("11kDa protein"), UQCRH
UQCRH
Cytochrome b-c1 complex subunit 6, mitochondrial is a protein that in humans is encoded by the UQCRH gene.Its gene product is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase Cytochrome b-c1 complex subunit 6, mitochondrial is a protein that in humans is encoded by the...
(cyt c1 Hinge protein), Rieske Protein presequence, "cyt. c1 associated protein", and UQCR http://www.ncbi.nlm.nih.gov/nucleotide/19923785("Rieske-associated protein").
Ubiquinol:ferricytochrome c oxidoreductase is found in mitochondria, photosynthetic bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and other prokaryotes. The general function of the complex
Protein complex
A multiprotein complex is a group of two or more associated polypeptide chains. If the different polypeptide chains contain different protein domain, the resulting multiprotein complex can have multiple catalytic functions...
is electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
transfer between two mobile redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
carriers, ubiquinol
Ubiquinol
Ubiquinol is an electron-rich form of coenzyme Q10.The natural ubiquinol form of coenzyme Q10 is 2,3-dimethoxy-5-methyl-6-poly prenyl-1,4-benzoquinol, where the polyprenylated side chain is 9-10 units long in mammals...
and cytochrome c
Cytochrome c
The Cytochrome complex, or cyt c is a small heme protein found loosely associated with the inner membrane of the mitochondrion. It belongs to the cytochrome c family of proteins. Cytochrome c is a highly soluble protein, unlike other cytochromes, with a solubility of about 100 g/L and is an...
; the electron transfer is coupled with proton
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
translocation across the membrane, thus generating proton-motive force in the form of an electrochemical potential that can drive ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
synthesis. In its structure and functions, the cytochrome bc1 complex bears extensive analogy to the cytochrome b6f
Cytochrome b6f complex
The cytochrome b6f complex is an enzyme found in the thylakoid membrane in chloroplasts of plants, cyanobacteria, and green algae, catalyzing the transfer of electrons from plastoquinol to plastocyanin...
complex of chloroplast
Chloroplast
Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...
s and cyanobacteria; cyt c1 plays an analogous role to cytochrome f, in spite of their different structures.