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glutamyl-tRNA Synthetase (glutamyl-trna + synthetase)

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Chemistry100%

Selected Abstracts

Structure of nondiscriminating glutamyl-tRNA synthetase from Thermotoga maritima

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2010
Takuhiro Ito
Aminoacyl-tRNA synthetases produce aminoacyl-tRNAs from the substrate tRNA and its cognate amino acid with the aid of ATP. Two types of glutamyl-tRNA synthetase (GluRS) have been discovered: discriminating GluRS (D-GluRS) and nondiscriminating GluRS (ND-GluRS). D-GluRS glutamylates tRNAGlu only, while ND-GluRS glutamylates both tRNAGlu and tRNAGln. ND-GluRS produces the intermediate Glu-tRNAGln, which is converted to Gln-tRNAGln by Glu-tRNAGln amidotransferase. Two GluRS homologues from Thermotoga maritima, TM1875 and TM1351, have been biochemically characterized and it has been clarified that only TM1875 functions as an ND-GluRS. Furthermore, the crystal structure of the T. maritima ND-GluRS, TM1875, was determined in complex with a Glu-AMP analogue at 2.0,Å resolution. The T. maritima ND-GluRS contains a characteristic structure in the connective-peptide domain, which is inserted into the catalytic Rossmann-fold domain. The glutamylation ability of tRNAGln by ND-GluRS was measured in the presence of the bacterial Glu-tRNAGln amidotransferase GatCAB. Interestingly, the glutamylation efficiency was not affected even in the presence of excess GatCAB. Therefore, GluRS avoids competition with GatCAB and glutamylates tRNAGln. [source]

Cloning, expression, crystallization and preliminary X-ray crystallographic analysis of glutamyl-tRNA synthetase (Xoo1504) from Xanthomonas oryzae pv. oryzae

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2009
Thanh Thi Ngoc Doan
The gltX gene from Xanthomonas oryzae pv. oryzae (Xoo1504) encodes glutamyl-tRNA synthetase (GluRS), one of the most important enzymes involved in bacterial blight (BB), which causes huge production losses of rice worldwide. GluRS is a class I-type aminoacyl-tRNA synthetase (aaRS) that is primarily responsible for the glutamylation of tRNAGlu. It plays an essential role in protein synthesis, as well as the regulation of cells, in all organisms. As it represents an important target for the development of new antibacterial drugs against BB, determination of the three-dimensional structure of GluRS is essential in order to understand its catalytic mechanism. In order to analyze its structure and function, the gltX gene was cloned and the GluRS enzyme was expressed, purified and then crystallized. A GluRS crystal belonging to the monoclinic space group C2 diffracted to 2.8,Å resolution and had unit-cell parameters a = 186.8, b = 108.4, c = 166.1,Å, , = 96.3°. The unit-cell volume of the crystal allowed the presence of six to eight monomers in the asymmetric unit, with a corresponding Matthews coefficient (VM) range of 2.70,2.02,Å3,Da,1 and a solvent-content range of 54.5,39.3%. [source]