| Abstract: | Models of atomic structure of eukaryotic translation termination complex containing mRNA, P-site tRNAPhe, human class-1 polypeptide release factor eRF1 and 80S ribosome were constructed. The method of computational modeling was applied. The modeling was based on the functional and structural similarity between tRNA and eFR1 bound in the ribosomal A site. Structural template for the modeling was a known structure of the 70S ribosome complexed with mRNA, P- and A-site tRNAsPhe. The eRF1 molecule bound to the ribosome undergone substantial conformational changes resulting in the mutual configuration of the N- and M-domains similar to tRNA shape. Two models of binding of eRF1 to mRNA at the A-site in the presence of P-site tRNA were generated and characterized by a shape complementarity between the mRNA stop codon and grooves of the different sides of the molecular surface of the fragment of alpha2-helix, NIKS loop and alpha-helix of the N-domain. In the model 1 the stop-codon nucleotides were at the equal distances from the N- and C-domains. In the model 2 the stop-codon was proximal to the NIKS and YxCxxxF motifs of the N-domain. Both models fit the genetic and biochemical data available so far. |
