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Aminoacyl tRNA synthetase

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 precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code.

Anticodon-binding domain of tRNA
leucyl-tRNA synthetase from Thermus thermophilus complexed with a post-transfer editing substrate analogue
Identifiers
SymbolAnticodon_2
PfamPF08264
InterProIPR013155
SCOP21ivs / SCOPe / SUPFAM
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
DALR anticodon binding domain 1
Thermus thermophilus arginyl-trna synthetase
Identifiers
SymbolDALR_1
PfamPF05746
Pfam clanCL0258
InterProIPR008909
SCOP21bs2 / SCOPe / SUPFAM
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
DALR anticodon binding domain 2
crystal structure of cysteinyl-tRNA synthetase binary complex with tRNACys
Identifiers
SymbolDALR_2
PfamPF09190
Pfam clanCL0258
InterProIPR015273
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary

This is sometimes called "charging" or "loading" the tRNA with an amino acid. Once the tRNA is charged, a ribosome can transfer the amino acid from the tRNA onto a growing peptide, according to the genetic code. Aminoacyl tRNA therefore plays an important role in RNA translation, the expression of genes to create proteins.

Mechanism edit

The synthetase first binds ATP and the corresponding amino acid (or its precursor) to form an aminoacyl-adenylate, releasing inorganic pyrophosphate (PPi). The adenylate-aaRS complex then binds the appropriate tRNA molecule's D arm, and the amino acid is transferred from the aa-AMP to either the 2'- or the 3'-OH of the last tRNA nucleotide (A76) at the 3'-end.

The mechanism can be summarized in the following reaction series:

  1. Amino Acid + ATP → Aminoacyl-AMP + PPi
  2. Aminoacyl-AMP + tRNA → Aminoacyl-tRNA + AMP

Summing the reactions, the highly exergonic overall reaction is as follows:

  • Amino Acid + tRNA + ATP → Aminoacyl-tRNA + AMP + PPi

Some synthetases also mediate an editing reaction to ensure high fidelity of tRNA charging. If the incorrect tRNA is added (aka. the tRNA is found to be improperly charged), the aminoacyl-tRNA bond is hydrolyzed. This can happen when two amino acids have different properties even if they have similar shapes—as is the case with valine and threonine.

The accuracy of aminoacyl-tRNA synthetase is so high that it is often paired with the word "superspecificity” when it is compared to other enzymes that are involved in metabolism. Although not all synthetases have a domain with the sole purpose of editing, they make up for it by having specific binding and activation of their affiliated amino acids. Another contribution to the accuracy of these synthetases is the ratio of concentrations of aminoacyl-tRNA synthetase and its cognate tRNA. Since tRNA synthetase improperly acylates the tRNA when the synthetase is overproduced, a limit must exist on the levels of aaRSs and tRNAs in vivo.[1][2]

Classes edit

There are two classes of aminoacyl tRNA synthetase, each composed of ten enzymes:[3][4]

  • Class I has two highly conserved sequence motifs. It aminoacylates at the 2'-OH of a terminal adenosine nucleotide on tRNA, and it is usually monomeric or dimeric (one or two subunits, respectively).
  • Class II has three highly conserved sequence motifs. It aminoacylates at the 3'-OH of a terminal adenosine on tRNA, and is usually dimeric or tetrameric (two or four subunits, respectively). Although phenylalanine-tRNA synthetase is class II, it aminoacylates at the 2'-OH.

The amino acids are attached to the hydroxyl (-OH) group of the adenosine via the carboxyl (-COOH) group.

Regardless of where the aminoacyl is initially attached to the nucleotide, the 2'-O-aminoacyl-tRNA will ultimately migrate to the 3' position via transesterification.

Bacterial aminoacyl-tRNA synthetases can be grouped as follows:[5]

Class Amino acids
I Arg, Cys, Gln, Glu, Ile, Leu, Met, Trp, Tyr, Val
II Ala, Asn, Asp, Gly, His, Lys, Pro, Phe, Ser, Thr

Amino acids which use class II aaRS seem to be evolutionarily older.[6]

 
A general structure of an aminoacyl-tRNA synthetase is shown here with an editing site as well as an activation site. The main difference between class I and class II synthetases is the activation site. Here you can see the general structure of the Rossmann fold seen in class I aaRSs and the general structure of antiparallel beta-sheets seen in class II aaRSs.
 
Alignment of the core domains of aminoacyl-tRNA synthetases class I and class II. Essential binding site residues (Backbone Brackets and Arginine Tweezers) are colored. N-terminal residues are highlighted in blue, C-terminal in red.

Structures edit

Both classes of aminoacyl-tRNA synthetases are multidomain proteins. In a typical scenario, an aaRS consists of a catalytic domain (where both the above reactions take place) and an anticodon binding domain (which interacts mostly with the anticodon region of the tRNA). Transfer-RNAs for different amino acids differ not only in their anticodon but also at other points, giving them slightly different overall configurations. The aminoacyl-tRNA synthetases recognize the correct tRNAs primarily through their overall configuration, not just through their anticodon.[7] In addition, some aaRSs have additional RNA binding domains and editing domains[8] that cleave incorrectly paired aminoacyl-tRNA molecules.

The catalytic domains of all the aaRSs of a given class are found to be homologous to one another, whereas class I and class II aaRSs are unrelated to one another. The class I aaRSs feature a cytidylyltransferase-like Rossmann fold seen in proteins like glycerol-3-phosphate cytidylyltransferase, nicotinamide nucleotide adenylyltransferase and archaeal FAD synthase, whereas the class II aaRSs have a unique fold related to biotin and lipoate ligases.

The alpha helical anticodon binding domain of arginyl-, glycyl- and cysteinyl-tRNA synthetases is known as the DALR domain after characteristic conserved amino acids.[9]

Aminoacyl-tRNA synthetases have been kinetically studied, showing that Mg2+ ions play an active catalytic role and therefore aaRs have a degree of magnesium dependence. Increasing the Mg2+ concentration leads to an increase in the equilibrium constants for the aminoacyl-tRNA synthetases’ reactions. Although this trend was seen in both class I and class II synthetases, the magnesium dependence for the two classes are very distinct. Class II synthetases have two or (more frequently) three Mg2+ ions, while class I only requires one Mg2+ ion.[10][11]

Beside their lack of overall sequence and structure similarity, class I and class II synthetases feature different ATP recognition mechanisms. While class I binds via interactions mediated by backbone hydrogen bonds, class II uses a pair of arginine residues to establish salt bridges to its ATP ligand. This oppositional implementation is manifested in two structural motifs, the Backbone Brackets and Arginine Tweezers, which are observable in all class I and class II structures, respectively. The high structural conservation of these motifs suggest that they must have been present since ancient times.[12]

Evolution edit

Most of the aaRSs of a given specificity are evolutionarily closer to one another than to aaRSs of another specificity. However, AsnRS and GlnRS group within AspRS and GluRS, respectively. Most of the aaRSs of a given specificity also belong to a single class. However, there are two distinct versions of the LysRS - one belonging to the class I family and the other belonging to the class II family.[citation needed]

The molecular phylogenies of aaRSs are often not consistent with accepted organismal phylogenies. That is, they violate the so-called canonical phylogenetic pattern shown by most other enzymes for the three domains of life - Archaea, Bacteria, and Eukarya. Furthermore, the phylogenies inferred for aaRSs of different amino acids often do not agree with one another. In addition, aaRS paralogs within the same species show a high degree of divergence between them. These are clear indications that horizontal transfer has occurred several times during the evolutionary history of aaRSs.[13]

A widespread belief in the evolutionary stability of this superfamily, meaning that every organism has all the aaRSs for their corresponding amino acids, is misconceived. A large-scale genomic analysis on ~2500 prokaryotic genomes showed that many of them miss one or more aaRS genes whereas many genomes have 1 or more paralogs.[14] AlaRS, GlyRS, LeuRS, IleRS and ValRS are the most evolutionarily stable members of the family. GluRS, LysRS and CysRS often have paralogs, whereas AsnRS, GlnRS, PylRS and SepRS are often absent from many genomes.

With the exception of AlaRS, it has been discovered that 19 out of the 20 human aaRSs have added at least one new domain or motif.[15] These new domains and motifs vary in function and are observed in various forms of life. A common novel function within human aaRSs is providing additional regulation of biological processes. There exists a theory that the increasing number of aaRSs that add domains is due to the continuous evolution of higher organisms with more complex and efficient building blocks and biological mechanisms. One key piece of evidence to this theory is that after a new domain is added to an aaRS, the domain becomes fully integrated. This new domain's functionality is conserved from that point on.[16]

As genetic efficiency evolved in higher organisms, 13 new domains with no obvious association with the catalytic activity of aaRSs genes have been added.

Application in biotechnology edit

In some of the aminoacyl tRNA synthetases, the cavity that holds the amino acid can be mutated and modified to carry unnatural amino acids synthesized in the lab, and to attach them to specific tRNAs. This expands the genetic code, beyond the twenty canonical amino acids found in nature, to include an unnatural amino acid as well. The unnatural amino acid is coded by a nonsense (TAG, TGA, TAA) triplet, a quadruplet codon, or in some cases a redundant rare codon. The organism that expresses the mutant synthetase can then be genetically programmed to incorporate the unnatural amino acid into any desired position in any protein of interest, allowing biochemists or structural biologists to probe or change the protein's function. For instance, one can start with the gene for a protein that binds a certain sequence of DNA, and, by directing an unnatural amino acid with a reactive side-chain into the binding site, create a new protein that cuts the DNA at the target-sequence, rather than binding it.

By mutating aminoacyl tRNA synthetases, chemists have expanded the genetic codes of various organisms to include lab-synthesized amino acids with all kinds of useful properties: photoreactive, metal-chelating, xenon-chelating, crosslinking, spin-resonant, fluorescent, biotinylated, and redox-active amino acids.[17] Another use is introducing amino acids bearing reactive functional groups for chemically modifying the target protein.

Certain diseases’ causation (such as neuronal pathologies, cancer, disturbed metabolic conditions, and autoimmune disorders) have been correlated to specific mutations of aminoacyl-tRNA synthetases. Charcot-Marie-Tooth (CMT) is the most frequent heritable disorder of the peripheral nervous system (a neuronal disease) and is caused by a heritable mutation in glycol-tRNA and tyrosyl-tRNA.[18] Diabetes, a metabolic disease, induces oxidative stress, which triggers a build up of mitochondrial tRNA mutations. It has also been discovered that tRNA synthetases may be partially involved in the etiology of cancer.[19] A high level of expression or modification of aaRSs has been observed within a range of cancers. A common outcome from mutations of aaRSs is a disturbance of dimer shape/formation which has a direct relationship with its function. These correlations between aaRSs and certain diseases have opened up a new door to synthesizing therapeutics.[20]

Noncatalytic domains edit

The novel domain additions to aaRS genes are accretive and progressive up the Tree of Life.[21][22][23] The strong evolutionary pressure for these small non-catalytic protein domains suggested their importance.[24] Findings beginning in 1999 and later revealed a previously unrecognized layer of biology: these proteins control gene expression within the cell of origin, and when released exert homeostatic and developmental control in specific human cell types, tissues and organs during adult or fetal development or both, including pathways associated with angiogenesis, inflammation, the immune response, the mechanistic target of rapamycin (mTOR) signalling, apoptosis, tumorigenesis, and interferon gamma (IFN-γ) and p53 signalling.[25][26][27][28][29][30][31][32][33]

Substrate Depletion edit

In 2022, it was discovered that aminoacyl-trna synthetases may incorporate alternative amino acids during shortages of their precursors. In particular, tryptophanyl-tRNA synthetase (WARS1) will incorporate phenylalanine during tryptophan depletion, essentially inducing a W>F codon reassignment.[34] Depletion of the other substrate of aminoacyl-tRNA synthetases, the cognate tRNA, may be relevant to certain diseases, e.g. Charcot–Marie–Tooth disease. It was shown that CMT-mutant glycyl-tRNA synthetase variants are still able to bind tRNA-gly but fail to release it, leading to depletion of the cellular pool of glycyl-tRNA-gly, what in turn results in stalling of the ribosome on glycine codons during mRNA translation.[35]

Clinical edit

Mutations in the mitochondrial enzyme have been associated with a number of genetic disorders including Leigh syndrome, West syndrome and CAGSSS (cataracts, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss and skeletal dysplasia syndrome).[36]

Prediction servers edit

  • ICAARS: B. Pawar, and GPS Raghava (2010) Prediction and classification of aminoacyl tRNA synthetases using PROSITE domains. BMC Genomics 2010, 11:507
  • MARSpred: Panwar B, Raghava GP (May 2012). "Predicting sub-cellular localization of tRNA synthetases from their primary structures". Amino Acids. 42 (5): 1703–13. doi:10.1007/s00726-011-0872-8. PMID 21400228. S2CID 2996097.
  • Prokaryotic AARS database: Chaliotis, et al. (Feb 2017). "The complex evolutionary history of aminoacyl-tRNA synthetases". Nucleic Acids Res. 45 (3): 1059–1068. doi:10.1093/nar/gkw1182. PMC 5388404. PMID 28180287.

See also edit

References edit

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External links edit

This article incorporates text from the public domain Pfam and InterPro: IPR015273
This article incorporates text from the public domain Pfam and InterPro: IPR008909

aminoacyl, trna, synthetase, aminoacyl, trna, synthetase, aars, also, called, trna, ligase, enzyme, that, attaches, appropriate, amino, acid, onto, corresponding, trna, does, catalyzing, transesterification, specific, cognate, amino, acid, precursor, compatibl. 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 precursor to one of all its compatible cognate tRNAs to form an aminoacyl tRNA In humans the 20 different types of aa tRNA are made by the 20 different aminoacyl tRNA synthetases one for each amino acid of the genetic code Anticodon binding domain of tRNAleucyl tRNA synthetase from Thermus thermophilus complexed with a post transfer editing substrate analogueIdentifiersSymbolAnticodon 2PfamPF08264InterProIPR013155SCOP21ivs SCOPe SUPFAMAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryDALR anticodon binding domain 1Thermus thermophilus arginyl trna synthetaseIdentifiersSymbolDALR 1PfamPF05746Pfam clanCL0258InterProIPR008909SCOP21bs2 SCOPe SUPFAMAvailable protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryDALR anticodon binding domain 2crystal structure of cysteinyl tRNA synthetase binary complex with tRNACysIdentifiersSymbolDALR 2PfamPF09190Pfam clanCL0258InterProIPR015273Available protein structures Pfam structures ECOD PDBRCSB PDB PDBe PDBjPDBsumstructure summaryThis is sometimes called charging or loading the tRNA with an amino acid Once the tRNA is charged a ribosome can transfer the amino acid from the tRNA onto a growing peptide according to the genetic code Aminoacyl tRNA therefore plays an important role in RNA translation the expression of genes to create proteins Contents 1 Mechanism 2 Classes 3 Structures 4 Evolution 5 Application in biotechnology 6 Noncatalytic domains 7 Substrate Depletion 8 Clinical 9 Prediction servers 10 See also 11 References 12 External linksMechanism editThe synthetase first binds ATP and the corresponding amino acid or its precursor to form an aminoacyl adenylate releasing inorganic pyrophosphate PPi The adenylate aaRS complex then binds the appropriate tRNA molecule s D arm and the amino acid is transferred from the aa AMP to either the 2 or the 3 OH of the last tRNA nucleotide A76 at the 3 end The mechanism can be summarized in the following reaction series Amino Acid ATP Aminoacyl AMP PPi Aminoacyl AMP tRNA Aminoacyl tRNA AMPSumming the reactions the highly exergonic overall reaction is as follows Amino Acid tRNA ATP Aminoacyl tRNA AMP PPiSome synthetases also mediate an editing reaction to ensure high fidelity of tRNA charging If the incorrect tRNA is added aka the tRNA is found to be improperly charged the aminoacyl tRNA bond is hydrolyzed This can happen when two amino acids have different properties even if they have similar shapes as is the case with valine and threonine The accuracy of aminoacyl tRNA synthetase is so high that it is often paired with the word superspecificity when it is compared to other enzymes that are involved in metabolism Although not all synthetases have a domain with the sole purpose of editing they make up for it by having specific binding and activation of their affiliated amino acids Another contribution to the accuracy of these synthetases is the ratio of concentrations of aminoacyl tRNA synthetase and its cognate tRNA Since tRNA synthetase improperly acylates the tRNA when the synthetase is overproduced a limit must exist on the levels of aaRSs and tRNAs in vivo 1 2 Classes editThere are two classes of aminoacyl tRNA synthetase each composed of ten enzymes 3 4 Class I has two highly conserved sequence motifs It aminoacylates at the 2 OH of a terminal adenosine nucleotide on tRNA and it is usually monomeric or dimeric one or two subunits respectively Class II has three highly conserved sequence motifs It aminoacylates at the 3 OH of a terminal adenosine on tRNA and is usually dimeric or tetrameric two or four subunits respectively Although phenylalanine tRNA synthetase is class II it aminoacylates at the 2 OH The amino acids are attached to the hydroxyl OH group of the adenosine via the carboxyl COOH group Regardless of where the aminoacyl is initially attached to the nucleotide the 2 O aminoacyl tRNA will ultimately migrate to the 3 position via transesterification Bacterial aminoacyl tRNA synthetases can be grouped as follows 5 Class Amino acidsI Arg Cys Gln Glu Ile Leu Met Trp Tyr ValII Ala Asn Asp Gly His Lys Pro Phe Ser ThrAmino acids which use class II aaRS seem to be evolutionarily older 6 nbsp A general structure of an aminoacyl tRNA synthetase is shown here with an editing site as well as an activation site The main difference between class I and class II synthetases is the activation site Here you can see the general structure of the Rossmann fold seen in class I aaRSs and the general structure of antiparallel beta sheets seen in class II aaRSs nbsp Alignment of the core domains of aminoacyl tRNA synthetases class I and class II Essential binding site residues Backbone Brackets and Arginine Tweezers are colored N terminal residues are highlighted in blue C terminal in red Structures editBoth classes of aminoacyl tRNA synthetases are multidomain proteins In a typical scenario an aaRS consists of a catalytic domain where both the above reactions take place and an anticodon binding domain which interacts mostly with the anticodon region of the tRNA Transfer RNAs for different amino acids differ not only in their anticodon but also at other points giving them slightly different overall configurations The aminoacyl tRNA synthetases recognize the correct tRNAs primarily through their overall configuration not just through their anticodon 7 In addition some aaRSs have additional RNA binding domains and editing domains 8 that cleave incorrectly paired aminoacyl tRNA molecules The catalytic domains of all the aaRSs of a given class are found to be homologous to one another whereas class I and class II aaRSs are unrelated to one another The class I aaRSs feature a cytidylyltransferase like Rossmann fold seen in proteins like glycerol 3 phosphate cytidylyltransferase nicotinamide nucleotide adenylyltransferase and archaeal FAD synthase whereas the class II aaRSs have a unique fold related to biotin and lipoate ligases The alpha helical anticodon binding domain of arginyl glycyl and cysteinyl tRNA synthetases is known as the DALR domain after characteristic conserved amino acids 9 Aminoacyl tRNA synthetases have been kinetically studied showing that Mg2 ions play an active catalytic role and therefore aaRs have a degree of magnesium dependence Increasing the Mg2 concentration leads to an increase in the equilibrium constants for the aminoacyl tRNA synthetases reactions Although this trend was seen in both class I and class II synthetases the magnesium dependence for the two classes are very distinct Class II synthetases have two or more frequently three Mg2 ions while class I only requires one Mg2 ion 10 11 Beside their lack of overall sequence and structure similarity class I and class II synthetases feature different ATP recognition mechanisms While class I binds via interactions mediated by backbone hydrogen bonds class II uses a pair of arginine residues to establish salt bridges to its ATP ligand This oppositional implementation is manifested in two structural motifs the Backbone Brackets and Arginine Tweezers which are observable in all class I and class II structures respectively The high structural conservation of these motifs suggest that they must have been present since ancient times 12 Evolution editMost of the aaRSs of a given specificity are evolutionarily closer to one another than to aaRSs of another specificity However AsnRS and GlnRS group within AspRS and GluRS respectively Most of the aaRSs of a given specificity also belong to a single class However there are two distinct versions of the LysRS one belonging to the class I family and the other belonging to the class II family citation needed The molecular phylogenies of aaRSs are often not consistent with accepted organismal phylogenies That is they violate the so called canonical phylogenetic pattern shown by most other enzymes for the three domains of life Archaea Bacteria and Eukarya Furthermore the phylogenies inferred for aaRSs of different amino acids often do not agree with one another In addition aaRS paralogs within the same species show a high degree of divergence between them These are clear indications that horizontal transfer has occurred several times during the evolutionary history of aaRSs 13 A widespread belief in the evolutionary stability of this superfamily meaning that every organism has all the aaRSs for their corresponding amino acids is misconceived A large scale genomic analysis on 2500 prokaryotic genomes showed that many of them miss one or more aaRS genes whereas many genomes have 1 or more paralogs 14 AlaRS GlyRS LeuRS IleRS and ValRS are the most evolutionarily stable members of the family GluRS LysRS and CysRS often have paralogs whereas AsnRS GlnRS PylRS and SepRS are often absent from many genomes With the exception of AlaRS it has been discovered that 19 out of the 20 human aaRSs have added at least one new domain or motif 15 These new domains and motifs vary in function and are observed in various forms of life A common novel function within human aaRSs is providing additional regulation of biological processes There exists a theory that the increasing number of aaRSs that add domains is due to the continuous evolution of higher organisms with more complex and efficient building blocks and biological mechanisms One key piece of evidence to this theory is that after a new domain is added to an aaRS the domain becomes fully integrated This new domain s functionality is conserved from that point on 16 As genetic efficiency evolved in higher organisms 13 new domains with no obvious association with the catalytic activity of aaRSs genes have been added Application in biotechnology editIn some of the aminoacyl tRNA synthetases the cavity that holds the amino acid can be mutated and modified to carry unnatural amino acids synthesized in the lab and to attach them to specific tRNAs This expands the genetic code beyond the twenty canonical amino acids found in nature to include an unnatural amino acid as well The unnatural amino acid is coded by a nonsense TAG TGA TAA triplet a quadruplet codon or in some cases a redundant rare codon The organism that expresses the mutant synthetase can then be genetically programmed to incorporate the unnatural amino acid into any desired position in any protein of interest allowing biochemists or structural biologists to probe or change the protein s function For instance one can start with the gene for a protein that binds a certain sequence of DNA and by directing an unnatural amino acid with a reactive side chain into the binding site create a new protein that cuts the DNA at the target sequence rather than binding it By mutating aminoacyl tRNA synthetases chemists have expanded the genetic codes of various organisms to include lab synthesized amino acids with all kinds of useful properties photoreactive metal chelating xenon chelating crosslinking spin resonant fluorescent biotinylated and redox active amino acids 17 Another use is introducing amino acids bearing reactive functional groups for chemically modifying the target protein Certain diseases causation such as neuronal pathologies cancer disturbed metabolic conditions and autoimmune disorders have been correlated to specific mutations of aminoacyl tRNA synthetases Charcot Marie Tooth CMT is the most frequent heritable disorder of the peripheral nervous system a neuronal disease and is caused by a heritable mutation in glycol tRNA and tyrosyl tRNA 18 Diabetes a metabolic disease induces oxidative stress which triggers a build up of mitochondrial tRNA mutations It has also been discovered that tRNA synthetases may be partially involved in the etiology of cancer 19 A high level of expression or modification of aaRSs has been observed within a range of cancers A common outcome from mutations of aaRSs is a disturbance of dimer shape formation which has a direct relationship with its function These correlations between aaRSs and certain diseases have opened up a new door to synthesizing therapeutics 20 Noncatalytic domains editThe novel domain additions to aaRS genes are accretive and progressive up the Tree of Life 21 22 23 The strong evolutionary pressure for these small non catalytic protein domains suggested their importance 24 Findings beginning in 1999 and later revealed a previously unrecognized layer of biology these proteins control gene expression within the cell of origin and when released exert homeostatic and developmental control in specific human cell types tissues and organs during adult or fetal development or both including pathways associated with angiogenesis inflammation the immune response the mechanistic target of rapamycin mTOR signalling apoptosis tumorigenesis and interferon gamma IFN g and p53 signalling 25 26 27 28 29 30 31 32 33 Substrate Depletion editIn 2022 it was discovered that aminoacyl trna synthetases may incorporate alternative amino acids during shortages of their precursors In particular tryptophanyl tRNA synthetase WARS1 will incorporate phenylalanine during tryptophan depletion essentially inducing a W gt F codon reassignment 34 Depletion of the other substrate of aminoacyl tRNA synthetases the cognate tRNA may be relevant to certain diseases e g Charcot Marie Tooth disease It was shown that CMT mutant glycyl tRNA synthetase variants are still able to bind tRNA gly but fail to release it leading to depletion of the cellular pool of glycyl tRNA gly what in turn results in stalling of the ribosome on glycine codons during mRNA translation 35 Clinical editMutations in the mitochondrial enzyme have been associated with a number of genetic disorders including Leigh syndrome West syndrome and CAGSSS cataracts growth hormone deficiency sensory neuropathy sensorineural hearing loss and skeletal dysplasia syndrome 36 Prediction servers editICAARS B Pawar and GPS Raghava 2010 Prediction and classification of aminoacyl tRNA synthetases using PROSITE domains BMC Genomics 2010 11 507 MARSpred Panwar B Raghava GP May 2012 Predicting sub cellular localization of tRNA synthetases from their primary structures Amino Acids 42 5 1703 13 doi 10 1007 s00726 011 0872 8 PMID 21400228 S2CID 2996097 Prokaryotic AARS database Chaliotis et al Feb 2017 The complex evolutionary history of aminoacyl tRNA synthetases Nucleic Acids Res 45 3 1059 1068 doi 10 1093 nar gkw1182 PMC 5388404 PMID 28180287 See also editTARS gene References edit McClain WH November 1993 Rules that govern tRNA identity in protein synthesis Journal of Molecular Biology 234 2 257 80 doi 10 1006 jmbi 1993 1582 PMID 8230212 Swanson R Hoben P Sumner Smith M Uemura H Watson L Soll D December 1988 Accuracy of in vivo aminoacylation requires proper balance of tRNA and aminoacyl tRNA synthetase Science 242 4885 1548 51 Bibcode 1988Sci 242 1548S doi 10 1126 science 3144042 PMID 3144042 tRNA Synthetases Archived from the original on 2012 08 04 Retrieved 2007 08 18 Delarue M 1995 Aminoacyl tRNA synthetases Structural Biology 5 1 48 55 doi 10 1016 0959 440x 95 80008 o PMID 7773747 Voet Donald Voet Judith G 2011 Biochemistry 4th ed Hoboken NJ Wiley ISBN 978 0 470 57095 1 Trifonov E N 2000 12 30 Consensus temporal order of amino acids and evolution of the triplet code Gene Papers presented at the Anton Dohrn Workshop 261 1 139 151 doi 10 1016 S0378 1119 00 00476 5 ISSN 0378 1119 PMID 11164045 Schimmel P Giege R Moras D Yokoyama S October 1993 An operational RNA code for amino acids and possible relationship to genetic code Proceedings of the National Academy of Sciences of the United States of America 90 19 8763 8 Bibcode 1993PNAS 90 8763S doi 10 1073 pnas 90 19 8763 PMC 47440 PMID 7692438 Molecule of the Month Aminoacyl tRNA Synthetases High Fidelity Archived from the original on 2013 10 20 Retrieved 2013 08 04 Wolf YI Aravind L Grishin NV Koonin EV August 1999 Evolution of aminoacyl tRNA synthetases analysis of unique domain architectures and phylogenetic trees reveals a complex history of horizontal gene transfer events Genome Research 9 8 689 710 doi 10 1101 gr 9 8 689 PMID 10447505 Airas RK December 2007 Magnesium dependence of the measured equilibrium constants of aminoacyl tRNA synthetases Biophysical Chemistry 131 1 3 29 35 doi 10 1016 j bpc 2007 08 006 PMID 17889423 Francklyn C Musier Forsyth K Martinis SA September 1997 Aminoacyl tRNA synthetases in biology and disease new evidence for structural and functional diversity in an ancient family of enzymes RNA 3 9 954 60 PMC 1369542 PMID 9292495 Kaiser F Bittrich S Salentin S Leberecht C Haupt VJ Krautwurst S Schroeder M Labudde D April 2018 Backbone Brackets and Arginine Tweezers delineate Class I and Class II aminoacyl tRNA synthetases PLOS Computational Biology 14 4 e1006101 Bibcode 2018PLSCB 14E6101K doi 10 1371 journal pcbi 1006101 PMC 5919687 PMID 29659563 Woese CR Olsen GJ Ibba M Soll D March 2000 Aminoacyl tRNA synthetases the genetic code and the evolutionary process Microbiology and Molecular Biology Reviews 64 1 202 36 doi 10 1128 MMBR 64 1 202 236 2000 PMC 98992 PMID 10704480 Chaliotis A Vlastaridis P Mossialos D Ibba M Becker HD Stathopoulos C Amoutzias GD February 2017 The complex evolutionary history of aminoacyl tRNA synthetases Nucleic Acids Research 45 3 1059 1068 doi 10 1093 nar gkw1182 PMC 5388404 PMID 28180287 Guo M Yang XL Schimmel P September 2010 New functions of aminoacyl tRNA synthetases beyond translation Nature Reviews Molecular Cell Biology 11 9 668 74 doi 10 1038 nrm2956 PMC 3042954 PMID 20700144 Lee SW Cho BH Park SG Kim S August 2004 Aminoacyl tRNA synthetase complexes beyond translation Journal of Cell Science 117 Pt 17 3725 34 doi 10 1242 jcs 01342 PMID 15286174 S2CID 29447608 Peter G Schultz Expanding the genetic code Xie W Schimmel P Yang XL December 2006 Crystallization and preliminary X ray analysis of a native human tRNA synthetase whose allelic variants are associated with Charcot Marie Tooth disease Acta Crystallographica Section F 62 Pt 12 1243 6 doi 10 1107 S1744309106046434 PMC 2225372 PMID 17142907 Kwon NH Kang T Lee JY Kim HH Kim HR Hong J Oh YS Han JM Ku MJ Lee SY Kim S December 2011 Dual role of methionyl tRNA synthetase in the regulation of translation and tumor suppressor activity of aminoacyl tRNA synthetase interacting multifunctional protein 3 Proceedings of the National Academy of Sciences of the United States of America 108 49 19635 40 Bibcode 2011PNAS 10819635K doi 10 1073 pnas 1103922108 PMC 3241768 PMID 22106287 Park SG Schimmel P Kim S August 2008 Aminoacyl tRNA synthetases and their connections to disease Proceedings of the National Academy of Sciences of the United States of America 105 32 11043 9 Bibcode 2008PNAS 10511043P doi 10 1073 pnas 0802862105 PMC 2516211 PMID 18682559 Ludmerer SW Schimmel P August 1987 Construction and analysis of deletions in the amino terminal extension of glutamine tRNA synthetase of Saccharomyces cerevisiae The Journal of Biological Chemistry 262 22 10807 13 doi 10 1016 S0021 9258 18 61035 X PMID 3301842 Eriani G Delarue M Poch O Gangloff J Moras D September 1990 Partition of tRNA synthetases into two classes based on mutually exclusive sets of sequence motifs Nature 347 6289 203 6 Bibcode 1990Natur 347 203E doi 10 1038 347203a0 PMID 2203971 S2CID 4324290 Cusack S December 1997 Aminoacyl tRNA synthetases Current Opinion in Structural Biology 7 6 881 9 doi 10 1016 s0959 440x 97 80161 3 PMID 9434910 Lo WS Gardiner E Xu Z Lau CF Wang F Zhou JJ Mendlein JD Nangle LA Chiang KP Yang XL Au KF Wong WH Guo M Zhang M Schimmel P July 2014 Human tRNA synthetase catalytic nulls with diverse functions Science 345 6194 328 32 Bibcode 2014Sci 345 328L doi 10 1126 science 1252943 PMC 4188629 PMID 25035493 Wakasugi K Schimmel P April 1999 Two distinct cytokines released from a human aminoacyl tRNA synthetase Science 284 5411 147 51 Bibcode 1999Sci 284 147W doi 10 1126 science 284 5411 147 PMID 10102815 Lareau LF Green RE Bhatnagar RS Brenner SE June 2004 The evolving roles of alternative splicing Current Opinion in Structural Biology 14 3 273 82 doi 10 1016 j sbi 2004 05 002 PMID 15193306 Wakasugi K Slike BM Hood J Otani A Ewalt KL Friedlander M Cheresh DA Schimmel P January 2002 A human aminoacyl tRNA synthetase as a regulator of angiogenesis Proceedings of the National Academy of Sciences of the United States of America 99 1 173 7 Bibcode 2002PNAS 99 173W doi 10 1073 pnas 012602099 PMC 117534 PMID 11773626 Tzima E Reader JS Irani Tehrani M Ewalt KL Schwartz MA Schimmel P January 2005 VE cadherin links tRNA synthetase cytokine to anti angiogenic function The Journal of Biological Chemistry 280 4 2405 8 doi 10 1074 jbc C400431200 PMID 15579907 S2CID 6943506 Kawahara A Stainier DY August 2009 Noncanonical activity of seryl transfer RNA synthetase and vascular development Trends in Cardiovascular Medicine 19 6 179 82 doi 10 1016 j tcm 2009 11 001 PMC 2846333 PMID 20211432 Zhou Q Kapoor M Guo M Belani R Xu X Kiosses WB Hanan M Park C Armour E Do MH Nangle LA Schimmel P Yang XL January 2010 Orthogonal use of a human tRNA synthetase active site to achieve multifunctionality Nature Structural amp Molecular Biology 17 1 57 61 doi 10 1038 nsmb 1706 PMC 3042952 PMID 20010843 Park SG Kim HJ Min YH Choi EC Shin YK Park BJ Lee SW Kim S May 2005 Human lysyl tRNA synthetase is secreted to trigger proinflammatory response Proceedings of the National Academy of Sciences of the United States of America 102 18 6356 61 doi 10 1073 pnas 0500226102 PMC 1088368 PMID 15851690 Arif A Jia J Moodt RA DiCorleto PE Fox PL January 2011 Phosphorylation of glutamyl prolyl tRNA synthetase by cyclin dependent kinase 5 dictates transcript selective translational control Proceedings of the National Academy of Sciences of the United States of America 108 4 1415 20 Bibcode 2011PNAS 108 1415A doi 10 1073 pnas 1011275108 PMC 3029695 PMID 21220307 Guo M Schimmel P March 2013 Essential nontranslational functions of tRNA synthetases Nature Chemical Biology 9 3 145 53 doi 10 1038 nchembio 1158 PMC 3773598 PMID 23416400 Pataskar Abhijeet Champagne Julien Nagel Remco Kenski Juliana Laos Maarja Michaux Justine Pak Hui Song Bleijerveld Onno B Mordente Kelly Navarro Jasmine Montenegro Blommaert Naomi 2022 03 09 Tryptophan depletion results in tryptophan to phenylalanine substitutants Nature 603 7902 721 727 Bibcode 2022Natur 603 721P doi 10 1038 s41586 022 04499 2 ISSN 1476 4687 PMC 8942854 PMID 35264796 Zuko Amila Mallik Moushami Thompson Robin Spaulding Emily L Wienand Anne R Been Marije Tadenev Abigail L D van Bakel Nick Sijlmans Celine Santos Leonardo A Bussmann Julia Catinozzi Marica Das Sarada Kulshrestha Divita Burgess Robert W Ignatova Zoya Storkebaum Erik 2021 09 03 tRNA overexpression rescues peripheral neuropathy caused by mutations in tRNA synthetase Science 373 6559 1161 1166 Bibcode 2021Sci 373 1161Z doi 10 1126 science abb3356 ISSN 1095 9203 PMC 8856733 PMID 34516840 Vona B Maroofian R Bellacchio E Najafi M Thompson K Alahmad A He L Ahangari N Rad A Shahrokhzadeh S Bahena P Mittag F Traub F Movaffagh J Amiri N Doosti M Boostani R Shirzadeh E Haaf T Diodato D Schmidts M Taylor RW Karimiani EG 2018 Expanding the clinical phenotype of IARS2 related mitochondrial disease BMC Med Genet 19 1 196 doi 10 1186 s12881 018 0709 3 PMC 6233262 PMID 30419932 External links editAmino Acyl tRNA Synthetases at the U S National Library of Medicine Medical Subject Headings MeSH AARS human gene location in the UCSC Genome Browser AARS human gene details in the UCSC Genome Browser This article incorporates text from the public domain Pfam and InterPro IPR015273 This article incorporates text from the public domain Pfam and InterPro IPR008909 Portal nbsp Biology 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