Histidyl-tRNA synthetase (HARS) also known as
histidine-tRNA ligase, is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
which in humans is encoded by the ''HARS''
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 ba ...
.
Function
Aminoacyl-tRNA synthetases are a class of enzymes that charge
tRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ac ...
s with their cognate
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s. The protein encoded by this gene is a
cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...
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 α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...
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 means "inflammation of many muscles" ('' poly-'' + '' myos-'' + ''-itis''). The inflammati ...
/
dermatomyositis
Dermatomyositis (DM) is a long-term inflammatory disorder which affects skin and the muscles. Its symptoms are generally a skin rash and worsening muscle weakness over time. These may occur suddenly or develop over months. Other symptoms may inc ...
.
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 using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...
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 t ...
and
EEF1G
Elongation factor 1-gamma is a protein that in humans is encoded by the ''EEF1G'' gene.
Function
This gene encodes a subunit of the elongation factor-1 complex, which is responsible for the enzymatic delivery of aminoacyl tRNAs to the ribosome. ...
.
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References
Further reading
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