HARS
Encyclopedia
Histidyl-tRNA synthetase (HARS) also known as histidine-tRNA ligase
, is an enzyme
which in humans is encoded by the HARS gene
.
s with their cognate amino acid
s. The protein encoded by this gene is a cytoplasm
ic enzyme which belongs to the class II family of aminoacyl tRNA synthetases. The enzyme is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of histidine
into proteins. The gene is located in a head-to-head orientation with HARSL
on chromosome five, where the homologous genes share a bidirectional promoter.
in the human autoimmune disease polymyositis
/dermatomyositis
.
with EEF1B2
and EEF1G
.
Histidine-tRNA ligase
In enzymology, a histidine-tRNA ligase is an enzyme that catalyzes the chemical reactionThe 3 substrates of this enzyme are ATP, L-histidine, and tRNA, whereas its 3 products are AMP, diphosphate, and L-histidyl-tRNA....
, is an enzyme
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...
which in humans is encoded by the HARS gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Function
Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNATransfer RNA
Transfer RNA is an adaptor molecule composed of RNA, typically 73 to 93 nucleotides in length, that is used in biology to bridge the three-letter genetic code in messenger RNA with the twenty-letter code of amino acids in proteins. The role of tRNA as an adaptor is best understood by...
s with their cognate amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s. The protein encoded by this gene is a cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
ic enzyme which belongs to the class II family of aminoacyl tRNA synthetases. The enzyme is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of histidine
Histidine
Histidine Histidine, an essential amino acid, has a positively charged imidazole functional group. It is one of the 22 proteinogenic amino acids. Its codons are CAU and CAC. Histidine was first isolated by German physician Albrecht Kossel in 1896. Histidine is an essential amino acid in humans...
into proteins. The gene is located in a head-to-head orientation with HARSL
HARS2
Probable histidyl-tRNA synthetase, mitochondrial is an enzyme that in humans is encoded by the HARS2 gene.-Further reading:...
on chromosome five, where the homologous genes share a bidirectional promoter.
Clinical significance
The gene product is a frequent target of autoantibodiesAutoantibody
An autoantibody is an antibody manufactured by the immune system that is directed against one or more of the individual's own proteins. It is derived from the Greek "auto" which means "self", "anti" which means "against" and "body"...
in the human autoimmune disease polymyositis
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
/dermatomyositis
Dermatomyositis
Dermatomyositis is a connective-tissue disease related to polymyositis and Bramaticosis that is characterized by inflammation of the muscles and the skin.- Causes :...
.
Interactions
HARS has been shown to interactProtein-protein interaction
Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...
with EEF1B2
EEF1B2
Elongation factor 1-beta is a protein that in humans is encoded by the EEF1B2 gene.-Interactions:EEF1B2 has been shown to interact with EEF1G and HARS.-Further reading:...
and EEF1G
EEF1G
Elongation factor 1-gamma is a protein that in humans is encoded by the EEF1G gene.-Interactions:EEF1G has been shown to interact with RECQL5, EEF1B2, EEF1D, LZTS1, HARS and Leucyl-tRNA synthetase.-Further reading:...
.