Nucleotide exchange factor
Encyclopedia
Nucleotide exchange factors (NEFs) are protein
s that stimulate the exchange (replacement) of nucleoside
diphosphates for nucleoside triphosphates bound to other proteins.
) nucleoside triphosphates–adenosine triphosphate
(ATP) or guanosine triphosphate
(GTP)–to their diphosphate forms (ADP
and GDP
) as a source of energy and to drive conformational changes. These changes in turn affect the structural, enzymatic
, or signalling properties of the protein.
Nucleotide exchange factors actively assist in the exchange of depleted nucleoside diphosphates for fresh nucleoside triphosphates. NEFs are specific for the nucleotides they exchange (ADP or GDP, but not both) and are often specific to a single protein or class of proteins with which they interact.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s that stimulate the exchange (replacement) of nucleoside
Nucleoside
Nucleosides are glycosylamines consisting of a nucleobase bound to a ribose or deoxyribose sugar via a beta-glycosidic linkage...
diphosphates for nucleoside triphosphates bound to other proteins.
Function
Many cellular proteins cleave (hydrolyzeHydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
) nucleoside triphosphates–adenosine triphosphate
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...
(ATP) or guanosine triphosphate
Guanosine triphosphate
Guanosine-5'-triphosphate is a purine nucleoside triphosphate. It can act as a substrate for the synthesis of RNA during the transcription process...
(GTP)–to their diphosphate forms (ADP
Adenosine diphosphate
Adenosine diphosphate, abbreviated ADP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside adenosine. ADP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase adenine....
and GDP
Guanosine diphosphate
Guanosine diphosphate, abbreviated GDP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside guanosine. GDP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase guanine....
) as a source of energy and to drive conformational changes. These changes in turn affect the structural, enzymatic
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
, or signalling properties of the protein.
Nucleotide exchange factors actively assist in the exchange of depleted nucleoside diphosphates for fresh nucleoside triphosphates. NEFs are specific for the nucleotides they exchange (ADP or GDP, but not both) and are often specific to a single protein or class of proteins with which they interact.
See also
- Nucleoside-diphosphate kinaseNucleoside-diphosphate kinaseNucleoside-diphosphate kinases are enzymes that catalyze the exchange of phosphate groups between different nucleoside diphosphates...
- Guanine nucleotide exchange factorGuanine nucleotide exchange factorGuanine nucleotide exchange factors activate monomeric GTPases by stimulating the release of guanosine diphosphate to allow binding of guanosine triphosphate . A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity...