Isoleucine—tRNA ligase

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In enzymology, an isoleucine—tRNA ligase (EC 6.1.1.5) is an enzyme that catalyzes a two-step reaction in which isoleucine is attached to its corresponding tRNA molecule:

Isoleucine + ATP → Isoleucyl-AMP + PPi

Isoleucyl-AMP + tRNA^Ile → Isoleucyl-tRNA^Ile + AMP

The 3 substrates of this enzyme are ATP, L-isoleucine, and tRNA(Ile), whereas its 3 products are AMP, diphosphate, and L-isoleucyl-tRNA(Ile).

This enzyme belongs to the family of ligases, to be specific those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds. The systematic name of this enzyme class is L-isoleucine:tRNAIle ligase (AMP-forming). Other names in common use include isoleucyl-tRNA synthetase, isoleucyl-transfer ribonucleate synthetase, isoleucyl-transfer RNA synthetase, isoleucine-transfer RNA ligase, isoleucine-tRNA synthetase, and isoleucine translase. This enzyme participates in valine, leucine and isoleucine biosynthesis and aminoacyl-trna biosynthesis.

As of late 2007, 10 structures have been solved for this class of enzymes, with PDB accession codes 1FFY, 1JZQ, 1JZS, 1QU2, 1QU3, 1UDZ, 1UE0, 1WK8, 1WNY, and 1WNZ.

• ALLEN EH, GLASSMAN E, SCHWEET RS (1960). "Incorporation of amino acids into ribonucleic acid. I. The role of activating enzymes". J. Biol. Chem. 235 (4): 1061–7. doi:10.1016/S0021-9258(18)69479-7. PMID 13792726.
• Berg P, Bergmann FH, Ofengand EJ, Dieckmann M (1961). "The enzymic synthesis of amino acyl derivatives of ribonucleic acid I. The mechanism of leucyl-, valyl-, isoleucyl- and methionyl ribonucleic acid formation". J. Biol. Chem. 236: 1726–1734. doi:10.1016/S0021-9258(19)63293-X.
• Bergmann FH, Berg P, Dieckmann M (1961). "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". J. Biol. Chem. 236: 1735–1740. doi:10.1016/S0021-9258(19)63294-1.