OLIGORIBONUCLEOTIDE AUGU(3), AUGU(6), AND (PU)6 INTERACTION WITH HUMAN PLACENTA 80S RIBOSOMES IN THE PRESENCE OF COGNATE TRANSFER-RNA AND PROTEIN-SYNTHESIZING SYSTEM

Interaction of human placenta 80S ribosomes with oligoribonucleotides AUGU(n) (n = 3 and 6) in the presence of cognate tRNAs and ''ribosome- free'' rabbit reticulocyte protein-synthesizing system was studied. Bi nding of the oligoribonucleotides to 80S ribosomes results in the form ation of stable posttranslocational complexes which may be easily isol ated by sucrose gradient centrifugation. The ratio of the components b ound in the complexes 80S . AUGU(3) . metPhe-tRNA(Phe), 80S . AUGU(6) . Met(Phe)(2)-tRNA(Phe), and 80S (pU)(6) (Phe)(2)-tRNA(Phe) is close t o the theoretical one. Basing on these results and data on the nonenzy matic binding of oligouridilates and Phe-tRNA(Phe) with 80S fibosomes, we may conclude that translation factors substantially stabilize the tRNA . 80S . oligoribonucleotide template complexes.