Interaction of 5-S RNA, 5.8-S RNA and tRNA with rat-liver ribosomal proteins.

Abstract

In order to ascertain 5-S RNA, 5.8-S RNA and tRNA binding proteins from eukaryotic ribosomes, affinity chromatography of the rat liver ribosomal 40-S and 60-S subunit proteins on immobilized RNAs was used. Rat liver 5-S RNA, 5.8-S RNA and tRNA were immobilized via 3′-end ribose to adipic-acid-hydrazide-epoxy-activated Sepharose 6B. Using two-dimensional polyacrylamide gel electrophoresis in a urea-urea system, the bound proteins were identified as follows: a) 5-S RNA was found to form a complex containing mainly proteins L6 and L18 of the large ribosomal subunit, whereas proteins L7, L8 and L35 were present in the complex to a lesser degree. b) 5.8-S RNA bound proteins L5, L6, L7 and L18 from the 60-S subunit. c) tRNA formed a complex containing proteins S3′, S6, S8, S9, S11, S14, S18 and S23/24 from the 40-S subunit and proteins L5, L6, L7, L8, L13, L14, L18, L19, L21, L25, L26, L27, L29, L31, L32, L35 and L36 from the 60-S subunit. From this list of proteins S6, S14 and S23/24 of the small and L6, L13, L19, L21, L26, L32, L35 and L36 of the large subunit gave stronger spots than the others. Proteins from the different complexes are overlapping to a certain extent. The results suggest that 5-S RNA and 5.8-S RNA are in a close neighbourhood in the rat liver ribosome. It is supposed that 5-S RNA, 5.8-S RNA and proteins L5, L6, L7, L8, L13, L19, L21, L26, L32, L35, L36 are at or near the eukaryotic peptidyltransferase centre.