2cfo
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Error-free protein biosynthesis is dependent on the reliable charging of | + | Error-free protein biosynthesis is dependent on the reliable charging of each tRNA with its cognate amino acid. Many bacteria, however, lack a glutaminyl-tRNA synthetase. In these organisms, tRNA(Gln) is initially mischarged with glutamate by a non-discriminating glutamyl-tRNA synthetase (ND-GluRS). This enzyme thus charges both tRNA(Glu) and tRNA(Gln) with glutamate. Discriminating GluRS (D-GluRS), found in some bacteria and all eukaryotes, exclusively generates Glu-tRNA(Glu). Here we present the first crystal structure of a non-discriminating GluRS from Thermosynechococcus elongatus (ND-GluRS(Tel)) in complex with glutamate at a resolution of 2.45 A. Structurally, the enzyme shares the overall architecture of the discriminating GluRS from Thermus thermophilus (D-GluRS(Tth)). We confirm experimentally that GluRS(Tel) is non-discriminating and present kinetic parameters for synthesis of Glu-tRNA(Glu) and of Glu-tRNA(Gln). Anticodons of tRNA(Glu) (34C/UUC36) and tRNA(Gln) (34C/UUG36) differ only in base 36. The pyrimidine base of C36 is specifically recognized in D-GluRS(Tth) by the residue Arg358. In ND-GluRS(Tel) this arginine residue is replaced by glycine (Gly366) presumably allowing both cytosine and the bulkier purine base G36 of tRNA(Gln) to be tolerated. Most other ND-GluRS share this structural feature, leading to relaxed substrate specificity. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Synechococcus elongatus]] | [[Category: Synechococcus elongatus]] | ||
| - | [[Category: Heinz, D | + | [[Category: Heinz, D W.]] |
[[Category: Jahn, D.]] | [[Category: Jahn, D.]] | ||
[[Category: Nickel, D.]] | [[Category: Nickel, D.]] | ||
| - | [[Category: Schubert, W | + | [[Category: Schubert, W D.]] |
| - | [[Category: Schulze, J | + | [[Category: Schulze, J O.]] |
[[Category: GLU]] | [[Category: GLU]] | ||
[[Category: aminoacyl-trna synthetase]] | [[Category: aminoacyl-trna synthetase]] | ||
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[[Category: protein biosynthesis]] | [[Category: protein biosynthesis]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:48:07 2008'' |
Revision as of 14:48, 21 February 2008
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NON-DISCRIMINATING GLUTAMYL-TRNA SYNTHETASE FROM THERMOSYNECHOCOCCUS ELONGATUS IN COMPLEX WITH GLU
Overview
Error-free protein biosynthesis is dependent on the reliable charging of each tRNA with its cognate amino acid. Many bacteria, however, lack a glutaminyl-tRNA synthetase. In these organisms, tRNA(Gln) is initially mischarged with glutamate by a non-discriminating glutamyl-tRNA synthetase (ND-GluRS). This enzyme thus charges both tRNA(Glu) and tRNA(Gln) with glutamate. Discriminating GluRS (D-GluRS), found in some bacteria and all eukaryotes, exclusively generates Glu-tRNA(Glu). Here we present the first crystal structure of a non-discriminating GluRS from Thermosynechococcus elongatus (ND-GluRS(Tel)) in complex with glutamate at a resolution of 2.45 A. Structurally, the enzyme shares the overall architecture of the discriminating GluRS from Thermus thermophilus (D-GluRS(Tth)). We confirm experimentally that GluRS(Tel) is non-discriminating and present kinetic parameters for synthesis of Glu-tRNA(Glu) and of Glu-tRNA(Gln). Anticodons of tRNA(Glu) (34C/UUC36) and tRNA(Gln) (34C/UUG36) differ only in base 36. The pyrimidine base of C36 is specifically recognized in D-GluRS(Tth) by the residue Arg358. In ND-GluRS(Tel) this arginine residue is replaced by glycine (Gly366) presumably allowing both cytosine and the bulkier purine base G36 of tRNA(Gln) to be tolerated. Most other ND-GluRS share this structural feature, leading to relaxed substrate specificity.
About this Structure
2CFO is a Single protein structure of sequence from Synechococcus elongatus with as ligand. Active as Glutamate--tRNA ligase, with EC number 6.1.1.17 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Crystal structure of a non-discriminating glutamyl-tRNA synthetase., Schulze JO, Masoumi A, Nickel D, Jahn M, Jahn D, Schubert WD, Heinz DW, J Mol Biol. 2006 Sep 1;361(5):888-97. Epub 2006 Jul 5. PMID:16876193
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