The systematic name of this enzyme class is L-threonine:tRNAThr ligase (AMP-forming). Other names in common use include threonyl-tRNA synthetase, threonyl-transfer ribonucleate synthetase, threonyl-transfer RNA synthetase, threonyl-transfer ribonucleic acid synthetase, threonyl ribonucleic synthetase, threonine-transfer ribonucleate synthetase, threonine translase, threonyl-tRNA synthetase, and TARS.
Threonine—tRNA ligase (TARS) belongs to the family of ligases, to be specific those forming carbon-oxygen bonds in tRNA and related compounds. More precisely, it belongs to the family of the aminoacyl-tRNA synthetases. These latter enzymes link amino acids to their cognate transfer RNAs (tRNA) in aminoacylation reactions that establish the connection between a specific amino acid and a nucleotide triplet anticodon embedded in the tRNA. During their long evolution, some of these enzymes have acquired additional functions, including roles in RNA splicing, RNA trafficking, transcriptional regulation, translational regulation, and cell signaling.
Threonyl-tRNA synthetase (TARS) from Escherichia coli is encoded by the thrSgene. It is a homodimeric enzyme that aminoacylates tRNA(Thr) with the amino acid threonine.[1] In addition, TARS has the ability to bind to its own messenger RNA (mRNA) immediately upstream of the AUG start codon, to inhibit its translation by competing with ribosome binding, and thus to negatively regulate the expression of its own gene. The cis-acting region responsible for the control, called operator, can be folded into four distinct domains.[2] Each of domains 2 and 4 can be folded in a stem and loop structure that mimics the anticodon arm of E. coli tRNA(Thr). Mutagenesis and biochemical experiments have shown that the two anticodon-like domains of the operator bind to the two tRNA(Thr) anticodon recognition sites (one per subunit) of the dimeric TARS in a quasi-symmetrical manner.[3][4]
The crystal structures of (i) TARS complexed with two tRNA(Thr) molecules,[5] and (ii) TARS complexed with two isolated domains 2,[6] have confirmed that TARS recognition is primarily governed by similar base-specific interactions between the anticodon loop of tRNA(Thr) and the loop of the operator domain 2. The same amino acids interact with the CGU anticodon sequence of tRNA(Thr) and the analogous residues in domain 2.
Related Research Articles
An aminoacyl-tRNA synthetase, 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.
In enzymology, an arginine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, an aspartate—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a glutamate—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a glutamine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, an isoleucine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a leucine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a lysine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a methionine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a phenylalanine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphopantothenate—cysteine ligase also known as phosphopantothenoylcysteine synthetase (PPCS) is an enzyme that catalyzes the chemical reaction which constitutes the second of five steps involved in the conversion of pantothenate to Coenzyme A. The reaction is:
In molecular biology, the protein domain SAICAR synthase is an enzyme which catalyses a reaction to create SAICAR. In enzymology, this enzyme is also known as phosphoribosylaminoimidazolesuccinocarboxamide synthase. It is an enzyme that catalyzes the chemical reaction
In enzymology, a proline—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a serine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a tryptophan-tRNA ligase is an enzyme that catalyzes the chemical reaction
Tyrosine—tRNA ligase, also known as tyrosyl-tRNA synthetase is an enzyme that is encoded by the gene YARS. Tyrosine—tRNA ligase catalyzes the chemical reaction
In enzymology, a valine—tRNA ligase is an enzyme that catalyzes the chemical reaction
Threonyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the TARS gene.
In molecular biology, the Cofactor transferase family is a family of protein domains that includes biotin protein ligases, lipoate-protein ligases A, octanoyl-(acyl carrier protein):protein N-octanoyltransferases, and lipoyl-protein:protein N-lipoyltransferases. The metabolism of the cofactors Biotin and lipoic acid share this family. They also share the target modification domain, and the sulfur insertion enzyme.
TRNA dimethylallyltransferase is an enzyme with systematic name dimethylallyl-diphosphate: tRNA dimethylallyltransferase. This enzyme catalyses the following chemical reaction
↑ Brunel, C; Caillet, J; Lesage, P; Graffe, M; Dondon, J; Moine, H; Romby, P; Ehresmann, C; Ehresmann, B; Grunberg-Manago, M; Springer, M (Oct 1992). "Domains of the Escherichia coli threonyl-tRNA synthetase translational operator and their relation to threonine tRNA isoacceptors". J Mol Biol. 227 (3): 621–634. doi:10.1016/0022-2836(92)90212-3. PMID1383551.
↑ Bedouelle, Hugues (Apr 1993). "Symmetrical interactions between the translational operator of the thrS gene and dimeric threonyl transfer RNA synthetase". J Mol Biol. 230 (3): 704–708. doi:10.1006/jmbi.1993.1190. PMID7683056.
↑ Torres-Larios, A; Dock-Bregeon, AC; Romby, P; Rees, B; Sankaranarayanan, R; Caillet, J; Springer, M; Ehresmann, C; Ehresmann, B; Moras, D (May 2002). "Structural basis of translational control by Escherichia coli threonyl tRNA synthetase". Nat Struct Biol. 9 (5): 343–347. doi:10.1038/nsb789. PMID11953757. S2CID2744686.
Further reading
Allen EH, Glassman E, Schweet RS (1960). "Incorporation of amino acids into ribonucleic acid. I. The role of activating enzymes". J. Biol. Chem. 235: 1061–7. PMID13792726.
Holley RW, Brunngraber EF, Saad F, Williams HH (1961). "Partial purification of the threonine- and tyrosine-activating enzymes from rat liver, and the effect of patassium ions on the activity of the tyrosine enzyme". J. Biol. Chem. 236: 197–9. PMID13715350.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
