Primary Citation of Related Structures: 1TYD, 2TS1, 3TS1
PubMed Abstract:
The crystal structure of tyrosyl-tRNA synthetase (EC 6.1.1.1) from Bacillus stearothermophilus has been refined to a crystallographic R-factor of 22.6% at 2.3 A resolution using a restrained least-squares procedure. In the final model the root-mean-square deviation from ideality for bond distances is 0 ...
The crystal structure of tyrosyl-tRNA synthetase (EC 6.1.1.1) from Bacillus stearothermophilus has been refined to a crystallographic R-factor of 22.6% at 2.3 A resolution using a restrained least-squares procedure. In the final model the root-mean-square deviation from ideality for bond distances is 0.018 A and for angle distances is 0.044 A. Each monomer consists of three domains: an alpha/beta domain (residues 1 to 220) containing a six-stranded beta-sheet, an alpha-helical domain (248 to 318) containing five helices, and a disordered C-terminal domain (319 to 418) for which the electron density is very weak and where it has not been possible to trace the polypeptide chain. Complexes of the enzyme with the catalytic intermediate tyrosyl adenylate and the inhibitor tyrosinyl adenylate have also been refined to R-factors of 23.9% at 2.8 A resolution and 21.0% at 2.7 A resolution, respectively. Formation of the complexes results in some crystal cracking, but there is no significant difference in the conformation of the polypeptide chain of the three structures described here. The relative orientation of the alpha/beta and alpha-helical domains is similar to that previously observed for the "A" subunit of a deletion mutant lacking the C-terminal domain. Differences between these structures are confined to surface loops that are involved in crystal packing. Tyrosyl adenylate and tyrosinyl adenylate bind in similar conformations within a deep cleft in the alpha/beta domain. The tyrosine moiety is in the equivalent position to that occupied by tyrosine in crystals of the truncated mutant and makes similar strong polar interactions with the enzyme. The alpha-phosphate group interacts with the main-chain nitrogen of Asp38. The two hydroxyl groups of the ribose form strong interactions with the protein. The 2'-hydroxyl group interacts with the carboxylate of Asp194 and the main-chain nitrogen of Gly192 while the 3'-hydroxyl interacts with a tightly bound water molecule (Wat326). The adenine moiety appears to make no significant polar interactions with the protein. The results of site-directed mutagenesis studies are examined in the light of these refined structures.
Related Citations:
Crystal Structure of a Deletion Mutant of a Tyrosyl-T/RNA Synthetase Complexed with Tyrosine Brick, P., Blow, D.M. (1987) J Mol Biol 194: 287
Interaction of Crystalline Tyrosol-T/RNA Synthetase with Adenosine, Adenosine Monophosphate, Adenosine Triphosphate and Pyrophosphate in the Presence of Tyrosinol Monteilhet, C., Blow, D.M., Brick, P. (1984) J Mol Biol 173: 477
Tyrosyl-T/RNA Synthetase Forms a Mononucleotide-Binding Fold Bhat, T.N., Blow, D.M., Brick, P., Nyborg, J. (1982) J Mol Biol 158: 699
A Density-Modification Method for the Improvement of Poorly Resolved Protein Electron-Density Maps Bhat, T.N., Blow, D.M. (1982) Acta Crystallogr A 38: 21
Binding of Tyrosine, Adenosine Triphosphate and Analogues to Crystalline Tyrosyl Transfer RNA Synthetase Monteilhet, C., Blow, D.M. (1978) J Mol Biol 122: 407
The Peptide Chain of Tyrosyl T/RNA Synthetase. No Evidence for a Super-Secondary Structure of Four Alpha-Helices Blow, D.M., Irwin, M.J., Nyborg, J. (1977) Biochem Biophys Res Commun 76: 728
The Crystal Structure of Tyrosyl-Transfer RNA Synthetase at 2.7 Angstroms Resolution Irwin, M.J., Nyborg, J., Reid, B.R., Blow, D.M. (1976) J Mol Biol 105: 577
Crystallization and Preliminary X-Ray Diffraction Studies on Tyrosyl-Transfer RNA Synthetase from Bacillus Stearothermophilus Reid, B.R., Koch, G.L.E., Boulanger, Y., Hartley, B.S., Blow, D.M. (1973) J Mol Biol 80: 199
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