title: Properties of phenylalanine transfer ribonucleic acid with modified 3'-terminal end in protein biosynthesis using a rabbit reticulocyte cell-free system: effect of the replacement of cytidine residues from the CpCpA end of tRNA by 5-iodocytidine or 2-thiocytidine.
abstract: Phe-tRNA Phe from yeast containing 2-thiocytidine or 5-iodocytidine in position 75 of the polynucleotide chain or Phe-tRNA Phe in which both positions 74 and 75 were substituted by 5-iodocytidine were investigated in the poly U-dependent polyphenylalanine synthesis on ribosomes from rabbit reticulocytes. Phe-tRNA Phe-Cps2CpA was nearly as active as the native Phe-tRNA Phe-CpCpA in the overall process. Phe-tRNA Phe-Cpi 5CpA as well as Phe-tRNA Phe-i5Cpi 5CpA were considerably less active than the native species. Investigation of individual steps of protein biosynthesis with these modified substrates revealed that the donor activity of peptidyl-tRNAs which contain 5-iodocytidine in their 3'-terminus is strongly imparied suggesting exacting structural requirements for the interaction of the CpCpA end of tRNA with the ribosomal P-site.
mesh_terms: D000818:Animals; D001483:Base Sequence; D003562:Cytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007700:Kinetics; D010445:Peptide Elongation Factors; D010649:Phenylalanine; D011072:Poly U; D014176:Protein Biosynthesis / Q000187:drug effects; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism
chemical_list: D010445:Peptide Elongation Factors; D012346:RNA, Transfer, Amino Acyl; D011072:Poly U; D010649:Phenylalanine; D003562:Cytidine