TETRACYCLINES INDUCE CHANGES IN ACCESSIBILITY OF RIBOSOMAL-PROTEINS TO PROTEASES

Limited proteolysis was used to test the interaction of tetracyclines and some of their derivatives with ribosomes. Proteolysis of the free ribosomes was compared with that of the ligand-bound ribosomes. The in teraction of different tetracyclines with ribosomes depends on their c hemical structure and produces both a protective effect and an increas ed susceptibility to proteases of some ribosomal proteins in the 30S a nd 50S subparticles. Most of the proteins affected by tetracycline act ion are located on the head of the 30S and interface side of the 50S s ubunits. On the grounds of the obtained data one of the antibiotic-bin ding regions can be located near the ribosomal peptidyl transferase ce nter. The effect of possible conformational changes induced by tetracy clines on the translation process is discussed.