ENGAGEMENT OF LOOP [[C]] OF 5S RIBOSOMAL-RNA IN PROTEIN-BIOSYNTHESIS IN PLANT-SYSTEM

Evidence was obtained for the involvement-of 5S rRNA in the elongation of the polypeptide chain during protein biosynthesis in the plant sys tem. Antisense DNA probes complementary to specific fragments of loop ''C'' a domain of 5S rRNA of lupin origin, inhibit the polypeptide syn thesis. We found that region 38-46 of loop ''C'' is exposed on the sur face of a ribosome in the pre-translocational state and is not availab le for hybridization in the post-translocational state. The mechanism of inhibition by a specific hybridized oligonucleotide can be explaine d through blocking the interaction between the conservative sequences: GT Psi C and GAAC of tRNA and 5S rRNA, respectively. Direct correlati on between structure and biological function is shown.