The crystal structure of phenylalanyl-tRNA synthetase (PheRS) from Thermus thermophilus, a class II aminoacyl-tRNA synthetase, complexed with phenylalanyl-adenylate (Phe-AMP) was determined at 2.6 A resolution. Crystals of native PheRS were soaked in a solution containing phenylalanine and ATP in the presence of Mn(2+) ions ...
The crystal structure of phenylalanyl-tRNA synthetase (PheRS) from Thermus thermophilus, a class II aminoacyl-tRNA synthetase, complexed with phenylalanyl-adenylate (Phe-AMP) was determined at 2.6 A resolution. Crystals of native PheRS were soaked in a solution containing phenylalanine and ATP in the presence of Mn(2+) ions. The first step of the aminoacylation reaction proceeds within the crystals, resulting in Phe-AMP formation at the active site. Specific recognition of the phenylalanine portion of the Phe-AMP is achieved by interactions of the phenyl ring of Phe-AMP with two neighbouring residues, Phealpha258 and Phealpha260. No manganese ions were observed within the active site; their role in the formation of the transition state may be assigned to a number of polar residues and water molecules. In the anomalous Fourier difference map, a divalent metal ion was detected at the interface of the alpha- and beta-subunits at a short distance from motif 3 residues participating in the substrate binding. A sulfate ion, which was identified on the protein surface, may mediate the interactions of PheRS with DNA. Visible conformational changes were detected in the active-site area adjacent to the position of the Phe-AMP, compared with the structure of PheRS complexed with a synthetic adenylate analogue (phenylalaninyl-adenylate). Based on the known structures of the substrate-free enzyme and its complexes with various ligands, a general scheme for the phenylalanylation mechanism is proposed.
Related Citations:
Structure pf phenylalanyl-tRNA synthetase from Thermus thermophilus Mosyak, L., Reshetnikova, L., Goldgur, Y., Delarue, M., Safro, M. (1995) Nat Struct Biol 2: 537
The crystal structure of phenylalanyl-tRNA synthetase from Thermus thermophilus complexed with cognate tRNA-Phe Goldgur, Y., Mosyak, L., Reshetnikova, L., Ankilova, V., Khodyreva, S., Safro, M. (1997) Structure 5: 59
Crystal Structures of phenylalnyl-tRNA synthetase complexed with phenylalanine and phenylalanyl-adenylate analogue Reshenikova, L., Moor, N., Lavrik, O., Vassyliev, D. (1999) J Mol Biol 287: 555
Organizational Affiliation:
Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
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