Biopolymers and cell. 1991. Volume 7. № 3. 60 - 65

KOVAL'CHUKE O. V., POTAPOV A. P.

Study on Yeast Phenylalanine tRNA Anti-codon Arm Interaction with Small Ribosomal Subunits of Rabbit Liver

Summary

    The 15-nucleotide analog of the yeast tRNAPhe anticodon arm appears to bind cooperatively to two equal in affinity sites of poly(U)-programmed 40S ribosome as well as intact tRNAPhe. However the fragment affinity for the ribosome is higher. This is mostly contributed by higher cooperative coefficient for the anticodon arm-ribosome complex formation. Cooperativity coefficients are 4 for tRNAphe and 47 for its anticodon arm, mean¬while, if cooperativity coefficient is not considered, association constants are 1,2-107 Mr1 (tRNAPhe) and 0,5-107 M-' (the arm) for each site at 2 °C and 20 mM Mg2+ concentration The correct codon-anticodon pairing is shown to play the key role in cooperativity origin. Template independent binding of tRNA to small ribosomal subunits is revealed, meanwhile, anticodon arm is not able to bind to 40S ribosomes in the absence of template.