Localization of the binding site of the tRNA~(Phe) 3'-terminal sequence on the subunits of Thermus thermophilus phenylalanyl-tRNA synthetase

摘要

Photoreactive tRNA~(Phe) derivative containing s~4U residue at the 3'-end, tRNA~(Phe)-s~4U-75, has been prepared by the tRNA nucleotidyltransferase catalyzed incorporation of s~4UMP into tRNA~(Phe) transcript lacking the 3'-terminal dinucleotide, tRNA~(Phe)-s~4U-75 has been shown to be efficiently cross-linked to T. thermophilus phenylalanyl-tRNA synthetase (PheRS), with all the criteria of an affinity labeling reagent being fulfilled. The main products of PheRS labeling, that differ in their electrophoretic mobility, arc resulted from cross-linking of tRNA~(Phe)-s~4U-75 to #beta# subunit of the enzyme. The data show the nucleotide at position 75 of tRNA~(Phe) to form base-specific contacts with #beta# subunit of T. thermophilus PheRS.