[Interaction of mRNA analogs--oligoribonucleotides AUGU3, AUGU6 and (pU)6 with 80S ribosomes from human placenta in the presence of related tRNA and a protein-synthesizing system].

Binding of oligoribonucleotides AUGUn (n-3 and 6) and (pU) to 80S ribosomes from human placenta in the presence of cognate tRNAs and a "ribosome-free" protein-synthesizing system from rabbit reticulocytes has been studied. The binding of the mRNA analogues resulted in formation of stable post-translocational complexes (which may be easily isolated by centrifugation in sucrose density gradient): 80S.AUGU3.MetPhe-tRNA(Phe); 80S.AUGU6.Met(Phe)2.tRNA(Phe); 80S.(pU)6.(Phe)2-tRNA(Phe). In these complexes the ratios of the bound ligands are close to the theoretically expected values. Comparison of the results obtained with the previously reported data on nonenzymatic binding of oligouridylates and Phe-tRNA(Phe) to 80S ribosomes lead one to the conclusion that translation factors significantly stabilize the complexes of tRNA with 80S ribosomes and oligoribonucleotide templates.