UQCR11 (ubiquinol-cytochrome c reductase, complex III sub-unit XI) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''UQCR11''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

. UQCR11 is the smallest known component of

Complex III Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

in the mitochondrial respiratory chain.

Structure

The UQCR11 gene, located on the p arm of

chromosome 19 Chromosome 19 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 19 spans more than 61.7 million base pairs, the building material of DNA. It is considered the most Gene density, gene-ri ...

in position 13.3, is made up of 3 exons and is 8,329 base pairs in length. The UQCR11 protein weighs 6.6 kDa and is composed of 56 amino acids. This gene encodes the smallest known component of the ubiquinol-cytochrome c reductase complex, which is also known as

and is part of the mitochondrial respiratory chain. In vertebrates, Complex III contains 11 sub-units: 3 respiratory sub-units, 2 core proteins and 6 low-molecular weight proteins. Proteobacterial complexes may contain as few as three sub-units.

Function

The UQCR11 protein may function as a binding factor for the iron-sulfur protein in

, which is ubiquitous in human cells. Complex III catalyzes the chemical reaction :QH₂ + 2 ferricytochrome c

\rightleftharpoons

Q + 2 ferrocytochrome c + 2 H⁺ Thus, the two substrates of Complex III are dihydroquinone (QH2) and ferri- (Fe³⁺) cytochrome c, whereas its 3

products Product may refer to: Business * Product (business), an item that can be offered to a market to satisfy the desire or need of a customer. * Product (project management), a deliverable or set of deliverables that contribute to a business solution ...

are

quinone The quinones are a class of organic compounds that are formally "derived from aromatic compounds benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with ...

(Q), ferro- (Fe²⁺) cytochrome c, and hydrogen ion, H⁺. This complex belongs to the family of

oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually ut ...

s, specifically those acting on diphenols and related substances as donor with a cytochrome as acceptor. This enzyme participates in

oxidative phosphorylation Oxidative phosphorylation(UK , US : or electron transport-linked phosphorylation or terminal oxidation, is the metabolic pathway in which Cell (biology), cells use enzymes to Redox, oxidize nutrients, thereby releasing chemical energy in order ...

. It has four cofactors: cytochrome c₁, cytochrome b-562, cytochrome b-566 and a 2-Iron

ferredoxin Ferredoxins (from Latin ''ferrum'': iron + redox, often abbreviated "fd") are iron–sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co. and applied t ...

of the Rieske type.

References

{{DEFAULTSORT:Uqcr11 Human proteins