2CFO

Non-Discriminating Glutamyl-tRNA Synthetase from Thermosynechococcus elongatus in Complex with Glu

Summary for 2CFO

• Entry DOI: 10.2210/pdb2cfo/pdb
• Descriptor: GLUTAMYL-TRNA SYNTHETASE, GLUTAMIC ACID (3 entities in total)
• Functional Keywords: ligase, aminoacyl-trna synthetase, atp-binding, nucleotide-binding
• Biological source: SYNECHOCOCCUS ELONGATUS
• Cellular location: Cytoplasm: Q8DLI5
• Total number of polymer chains: 2
• Total formula weight: 110870.22

Authors

Schulze, J.O.,Nickel, D.,Schubert, W.-D.,Jahn, D.,Heinz, D.W. (deposition date: 2006-02-22, release date: 2006-08-16, Last modification date: 2023-12-13)

Primary citation

Schulze, J.O.,Masoumi, A.,Nickel, D.,Jahn, M.,Jahn, D.,Schubert, W.-D.,Heinz, D.W.
Crystal Structure of a Non-Discriminating Glutamyl- tRNA Synthetase.
J.Mol.Biol., 361:888-, 2006

PubMed Abstract: 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.

PubMed: 16876193
DOI: 10.1016/J.JMB.2006.06.054

Experimental method

X-RAY DIFFRACTION (2.45 Å)