Histidyl-tRNA synthetase (HARS) also known as
histidine-tRNA ligase, is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
which in humans is encoded by the ''HARS''
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 ...
.
Function
Aminoacyl-tRNA synthetases are a class of enzymes that charge
tRNA
Transfer ribonucleic acid (tRNA), formerly referred to as soluble ribonucleic acid (sRNA), is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes). In a cell, it provides the physical link between the gene ...
s with their cognate
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...
s. The protein encoded by this gene is a
cytoplasm
The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...
ic enzyme which belongs to the class II family of
aminoacyl tRNA synthetases
An aminoacyl-tRNA synthetase (aaRS or ARS), also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its pre ...
. The enzyme is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of
histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an Amine, α-amino group (which is in the protonated –NH3+ form under Physiological condition, biological conditions), a carboxylic ...
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.
Clinical significance
The gene product is a frequent target of
autoantibodies
An autoantibody is an antibody (a type of protein) produced by the immune system that is directed against one or more of the individual's own proteins. Many autoimmune diseases (notably lupus erythematosus) are associated with such antibodies.
Pr ...
in the human autoimmune disease
polymyositis
Polymyositis (PM) is a type of chronic inflammation of the muscles ( inflammatory myopathy) related to dermatomyositis and inclusion body myositis. Its name is derived . The inflammation of polymyositis is mainly found in the endomysial layer ...
/
dermatomyositis
Dermatomyositis (DM) is a Chronic condition, long-term inflammatory disorder, inflammatory Autoimmune disease, autoimmune disorder which affects the skin and the muscles. Its symptoms are generally a skin rash and worsening muscle weakness over ...
.
Interactions
HARS has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization advocating for the legal and human rights of children with intersex traits. The organization was founded in 2006 and fo ...
with
EEF1B2
Elongation factor 1-beta is a protein that in humans is encoded by the ''EEF1B2'' gene.
Function
This gene encodes a translation elongation factor. The protein is a guanine nucleotide exchange factor involved in the transfer of aminoacylated ...
and
EEF1G.
[
]
References
Further reading
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