Polynucleotide-protein interactions in the translation system. Identification of proteins interacting with tRNA in the A- and P-sites of E. coli ribosomes.

Ultraviolet irradiation (lambda = 254 nm) of ternary complexes of E. coli 70 S ribosomes with poly(U) and either Phe-tRNAPhe (in the A-site) or NAcPhe-tRNAPhe (in the P-site) effectively induces covalent linking of tRNA with a limited number of ribosomal proteins. The data obtained indicate that in both sites tRNA is in contact with proteins of both 30 S and 50 S subunits (S5, S7, S9, S10, L2, L6 and L16 proteins in the A-site and S7, S9, S11, L2, L4, L7/L12 and L27 proteins in the P-site). Similar sets of proteins are in contact with total aminoacyl-tRNA and N-acetylaminoacyl-tRNA. However, here no contacts of tRNA in the P-site with the S7 and L25/S17 proteins were revealed, whereas in the A-site total aminoacyl-tRNA contacts L7/L12. Proteins S9, L2 and, probably, S7 and L7/L12 are common to both sites.