Specific interaction of anticodon loop residues with yeast phenylalanyl-tRNA synthetase.
Thirteen different yeast tRNAPhe variants with single nucleotide changes in positions 34-37 in the anticodon region were prepared by an enzymatic procedure described previously. Aminoacylation kinetics using purified yeast phenylalanyl-tRNA synthetase revealed that the level of aminoacylation was very different for different sequences inserted. The low level of aminoacylation was the result of a steady state between a slow forward reaction rate and spontaneous deacylation of the product. Aminoacylation kinetics performed at higher synthetase concentrations revealed that substitution at position 34 in tRNAPhe decreased the Km nearly 10-fold but only had a small effect on Vmax. Similar substitutions at positions 35, 36, and 37 had a lesser effect. These data suggest a sequence-specific contact between the anticodon of yeast tRNAPhe and the cognate synthetase.
D000215:Acylation; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000926:Anticodon / Q000378:metabolism*; D001483:Base Sequence; D007700:Kinetics; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism*; D012331:RNA, Fungal / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013379:Substrate Specificity
D000926:Anticodon; D012331:RNA, Fungal; D012346:RNA, Transfer, Amino Acyl; D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases; D010652:Phenylalanine-tRNA Ligase