Identity of the ribosomal proteins involved in the interaction with elongation factor G

Rabbit antibodies produced against 50 of the 55 individually purified ribosomal proteins of Escherichia coli were tested for their ability to interfere with the formation of the ribosome.EF-G.GDP complex. Only antibodies produced against proteins L7 and L12 inhibited complex formation, and they did so completely. These two proteins were previously shown to be immunologically indistinguishable and necessary for the interaction between ribosomes and EF-G. The present data are consistent with the view that the interaction between ribosomes and EF-G that results in GTP hydrolysis occurs on, and is limited to, proteins L7 and L12 on the surface of the 50S ribosomal subunit.