Carbodiimide-induced protein--RNA crosslinking in mammalian ribosomal subunits

RNA--protein interactions in the 60 S subunits of rat liver ribosomes were studied using 1-ethyl-3-dimethylaminopropyl carbodiimide (EDC) under conditions which neither changed the sedimentation coefficient of subunits nor the intactness of their rRNA. EDC induced RNA--protein and protein--protein crosslinkings. Proteins crosslinked to 28 S RNA were identified by two-dimensional gel electrophoreses as L17, L19, L23a and L37a, shown to react with 28 S RNA when using a low dose of UV radiation. Attempts have also been made to use EDC for the studies of RNA--protein interactions in 40 S ribosomal subunits.