Thermostable valyl-tRNA, isoleucyl-tRNA and methionyl-tRNA synthetases from an extreme thermophile Thermus thermophilus HB8: protein structure and Zn2+ binding.
Thermostable valyl-tRNA, isoleucyl-tRNA and methionyl-tRNA synthetases have been purified from an extreme thermophile, Thermus thermophilus HB8. Valyl-tRNA and isoleucyl-tRNA synthetases are found to be monomer proteins (Mr 108000 and 129000, respectively), while methionyl-tRNA synthetase is a dimer protein (Mr 150000). These enzymes are very similar with respect to amino acid compositions and alpha-helix contents as estimated by circular dichroism analyses. Furthermore, two Zn2+ are tightly bound to each of these synthetases. These data suggest that valyl-tRNA and isoleucyl-tRNA synthetases consist of two domains, each corresponding to the subunit of methionyl-tRNA synthetase.
D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D004355:Drug Stability; D006358:Hot Temperature; D007533:Isoleucine-tRNA Ligase / Q000378:metabolism*; D046911:Macromolecular Substances; D008718:Methionine-tRNA Ligase / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding; D011487:Protein Conformation; D013824:Thermus / Q000201:enzymology*; D014637:Valine-tRNA Ligase / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D046911:Macromolecular Substances; D000604:Amino Acyl-tRNA Synthetases; D008718:Methionine-tRNA Ligase; D007533:Isoleucine-tRNA Ligase; D014637:Valine-tRNA Ligase; D015032:Zinc