View source for Methionine—tRNA ligase

{{infobox enzyme
| Name       = methionine—tRNA ligase
| EC_number  = 6.1.1.10
| CAS_number = 9033-22-1
| GO_code    = 0004825
| image      = 5goy.jpg
| width      = 270
| caption    = Methionine--tRNA ligase monomer, Human
}}
In [[enzymology]], a '''methionine—tRNA ligase''' ({{EnzExplorer|6.1.1.10}}) is an [[enzyme]] that [[catalysis|catalyzes]] the [[chemical reaction]]

:ATP + L-methionine + tRNAMet <math>\rightleftharpoons</math> AMP + diphosphate + L-methionyl-tRNAMet

The 3 [[substrate (biochemistry)|substrates]] of this enzyme are [[adenosine triphosphate|ATP]], [[L-methionine]], and [[tRNA(Met)]], whereas its 3 [[product (chemistry)|products]] are [[adenosine monophosphate|AMP]], [[diphosphate]], and [[L-methionyl-tRNA(Met)]].

This enzyme belongs to the family of [[ligase]]s, to be specific those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds.  The [[List of enzymes|systematic name]] of this enzyme class is '''L-methionine:tRNAMet ligase (AMP-forming)'''. Other names in common use include '''methionyl-tRNA synthetase''', '''methionyl-transfer ribonucleic acid synthetase''', '''methionyl-transfer ribonucleate synthetase''', '''methionyl-transfer RNA synthetase''', '''methionine translase''', and '''MetRS'''.  This enzyme participates in 3 [[metabolism|metabolic pathways]]: [[methionine metabolism]], [[selenoamino acid metabolism]], and [[aminoacyl-trna biosynthesis]].

== Role in oxidative stress ==
During [[oxidative stress]], methionine—tRNA ligase might be [[Phosphorylation|phosphorylated]], which results in [[Enzyme promiscuity|promiscuity]] of this enzyme, where it aminoacylates methionine to various non-Met tRNAs. This in turn leads to substitution of amino acids in proteins with methionine, which helps relieve oxidative stress in the cell.<ref>{{cite journal | vauthors = Aledo JC | title = Methionine in proteins: The Cinderella of the proteinogenic amino acids | journal = Protein Science | volume = 28 | issue = 10 | pages = 1785–1796 | date = October 2019 | pmid = 31359525 | pmc = 6739822 | doi = 10.1002/pro.3698 }}</ref>

==Structural studies==

As of late 2007, 21 [[tertiary structure|structures]] have been solved for this class of enzymes, with [[Protein Data Bank|PDB]] accession codes {{PDB link|1A8H}}, {{PDB link|1F4L}}, {{PDB link|1MEA}}, {{PDB link|1MED}}, {{PDB link|1MKH}}, {{PDB link|1P7P}}, {{PDB link|1PFU}}, {{PDB link|1PFV}}, {{PDB link|1PFW}}, {{PDB link|1PFY}}, {{PDB link|1PG0}}, {{PDB link|1PG2}}, {{PDB link|1QQT}}, {{PDB link|1RQG}}, {{PDB link|1WOY}}, {{PDB link|2CSX}}, {{PDB link|2CT8}}, {{PDB link|2D54}}, {{PDB link|2D5B}}, {{PDB link|2DJV}}, and {{PDB link|2HSN}}.

== References ==
{{reflist}}

== Further reading ==
{{refbegin}}
* {{cite journal | vauthors = Bergmann FH, Berg P, Dieckmann M | year = 1961 | title = The enzymic synthesis of amino acyl derivatives of ribonucleic acid II. The preparation of leucyl-, valyl-, isoleucyl- and methionyl ribonucleic acid synthetases from Escherichia coli | journal = J. Biol. Chem.  | volume = 236 | pages = 1735&ndash;1740 | doi = 10.1016/S0021-9258(19)63294-1 | doi-access = free }}
* {{cite journal | vauthors = Lee CP, Dyson MR, Mandal N, Varshney U, Bahramian B, RajBhandary UL | title = Striking effects of coupling mutations in the acceptor stem on recognition of tRNAs by Escherichia coli Met-tRNA synthetase and Met-tRNA transformylase | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 89 | issue = 19 | pages = 9262–9266 | date = October 1992 | pmid = 1409632 | pmc = 50106 | doi = 10.1073/pnas.89.19.9262 | doi-access = free | bibcode = 1992PNAS...89.9262L }}
{{refend}}

{{Ligases CO CS and CN}}
{{Enzymes}}
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{{DEFAULTSORT:Methionine-tRNA ligase}}
[[Category:EC 6.1.1]]
[[Category:Enzymes of known structure]]


{{ligase-stub}}