[Affinity labeling of ribosomes from Escherichia coli with 4-(N-2-chloroethyl, N-methylamino)-benzaldehyde actyl derivatives of oligouridylates].

4-(N-2-chloroethyl-N-methylamino)-benzaldehyde acetyl derivatives of penta-., hexa, hepta-, octauridylates were used for localization of the structures organizing the mRNA-binding centre of ribosomes. These derivatives, alike free oligonucleotides, stimulate the binding of phenylalanyl-tRNA to ribosomes. Within the specific complex all the oligonucleotide derivatives alkylated the 30S ribosomal subunit. Octauridylate and hexauridylate derivatives specifically alkylated also the 50S subunit of ribosomes. Polyuridylic acid protected ribosomal subunits from alkylation. In the 30S subunit the derivatives modify 16S RNA and proteins: S4, S5, S7, S9, S13, S15, S18, S21. It was found that oligouridylate derivatives of different length alkylate different proteins.