threonyl-transfer ribonucleate synthetase
threonyl-transfer ribonucleic acid synthetase
threonine-transfer ribonucleate synthetase
This enzyme belongs to the class-IIa aminoacyl-tRNA synthetase family. Although the tertiary structures with magnesium ions have not been determined yet, Mg2+ ion might be bound to Glu365 (of 1evk), according to the paper [13]. According to the literature [7] & [8], zinc ion is involved in threonine recognition, discriminating it from other amino acids. According to the literature [13], this enzyme catalyzes two successive transfer reactions. Firstly, it transfers the adenylate from ATP (the first substrate) to the carboxylate of the second substrate, threonine, resulting in the formation of threonyl-adenylate (intermediate) and the release of the inorganic pyrophosphate. Secondly, it transfers the acyl group from the intermediate to the 3'-OH of tRNA(Thr). The first transfer reaction proceeds as follows (see [13]): (1) The first substrate, ATP, adopts a bent conformation so that the alpha-phosphate group faces the carboxylate of the threonine. (2) Arg363 stabilizes the negatively charged groups, the acceptor group (the carboxylate) and the transferred group (apha-phosphate of ATP), by neutralizing the charged groups. A magnesium ion coordinated to Glu365 also stabilizes the leaving group, the beta- and gamma-phosphphate moieties (or pyrophosphate). (3) The stabilization of the negatively charged groups leads to an in-line nucleophilic attack by the carboxylate group on the alpha-phosphorus atom, by associative mechanism (SN2-like mechanism). (4) The pentacovalent transition state is stabilized by three basic residues (Arg363, Arg375 & Lys465), and the magnesium ion. Here, the leaving group, the pyrophosphate, is stabilized by the magnesium ion, Arg375 and Lys465. (5) The leaving group, the inorganic pyrophosphate, leaves the active site, probably together with the two bridging magnesium ions. The second acyl transfer reaction has not been elucidated yet.
Replication Terminator Protein; Chain A, domain 2
Threonyl-tRNA Synthetase; Chain A, domain 2
Glycine, serine and threonine metabolism
Crystals of threonyl-tRNA synthetase from Thermus thermophilus. Preliminary crystallographic data.
Structural basis of translational control by Escherichia coli threonyl tRNA synthetase.
Induced fit and kinetic mechanism of adenylation catalyzed by Escherichia coli threonyl-tRNA synthetase.
Elucidation of tRNA-dependent editing by a class II tRNA synthetase and significance for cell viability.
Conformational movements and cooperativity upon amino acid, ATP and tRNA binding in threonyl-tRNA synthetase.
Crystallization of threonyl-tRNA synthetase from Thermus thermophilus and preliminary crystallographic data.
The structure of threonyl-tRNA synthetase-tRNA(Thr) complex enlightens its repressor activity and reveals an essential zinc ion in the active site.
Structure of Hsp15 reveals a novel RNA-binding motif.
Sequence analysis and modular organization of threonyl-tRNA synthetase from Thermus thermophilus and its interrelation with threonyl-tRNA synthetases of other origins.
Role of zinc ion in translational accuracy becomes crystal clear.
Zinc ion mediated amino acid discrimination by threonyl-tRNA synthetase.
X-RAY CRYSTALLOGRAPHY (1.55 ANGSTROMS) OF 242-642.
The fidelity of the translation of the genetic code.
The modular structure of Escherichia coli threonyl-tRNA synthetase as both an enzyme and a regulator of gene expression.
Transfer RNA-mediated editing in threonyl-tRNA synthetase. The class II solution to the double discrimination problem.
CYS 336;HIS 387;HIS 517(Zinc binding);GLU 367(Magnesium binding)
CYS 334;HIS 385;HIS 511(Zinc binding);GLU 365(Magnesium binding)