title: Direct cross-linking of heptauridilate to E. coli ribosomes by water-soluble carbodiimide in the complex stabilized by codon-anticodon interaction at both A- and P-sites.
abstract: Affinity labelling of E. coli ribosomes is performed by treatment with water-soluble carbodiimide of the complex of ribosomes with (pU)7, tRNAPhe at the P-site and with Phe-tRNAPhe (complex I) and without Phe-tRNAPhe (complex II) at the A-site. The extent of modification is, respectively, 0.06 and 0.026 mol (pU)7 per mol ribosomes. Protein S3 is found as a single labelled protein in complex I, whereas S7, S8, L25 are modified in complex II. Thus, in the absence of a large spacer group within the complex stabilized by codon-anticodon interactions at both A- and P-sites, a highly selective modification occurs.
mesh_terms: D000345:Affinity Labels; D000926:Anticodon / Q000378:metabolism*; D001665:Binding Sites; D001667:Binding, Competitive; D003028:CME-Carbodiimide; D002234:Carbodiimides; D055598:Chemical Phenomena; D002621:Chemistry; D003062:Codon / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D009841:Oligonucleotides; D009843:Oligoribonucleotides; D012333:RNA, Messenger / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D014500:Uracil Nucleotides
chemical_list: D000345:Affinity Labels; D000926:Anticodon; D002234:Carbodiimides; D003062:Codon; D009841:Oligonucleotides; D009843:Oligoribonucleotides; D012333:RNA, Messenger; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; D014500:Uracil Nucleotides; C037801:tRNA, phenylalanylphenylalanine-; D003028:CME-Carbodiimide; C045554:heptauridylic acid; D012343:RNA, Transfer