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 residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

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

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. 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 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 couples thi ...

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 58.6 million base pairs, the building material of DNA. It is considered the most gene-rich chromosom ...

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

. 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 Iron–sulfur proteins (or iron–sulphur proteins in British spelling) are proteins characterized by the presence of iron–sulfur clusters containing sulfide-linked di-, tri-, and tetrairon centers in variable oxidation states. Iron–sulfur cl ...

, 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 serves as a solution to a specific consumer problem. * Product (project management), a deliverable or set of deliverables that contribute to a business solution Mathematics * Produ ...

are quinone (Q), ferro- (Fe²⁺) cytochrome c, and 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 u ...

s, specifically those acting on diphenols and related substances as donor with a cytochrome as acceptor. This enzyme participates in oxidative phosphorylation. It has four cofactors: cytochrome c₁, cytochrome b-562, cytochrome b-566 and a 2-Iron ferredoxin of the Rieske type.

References

{{DEFAULTSORT:Uqcr11 Human proteins