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. Copyright © 1978, Wiley Blackwell. All rights reserved