Translational fidelity in Escherichia coli: antagonistic effects of neaA and ramC gene products on the ribosome function.

A double mutant carrying the ramC and neaA mutations has been constructed by Plvir transductions. This mutant, which carries alterations in ribosomal proteins S5 and S17, behaves like to wild-type bacteria in the following respects: it no longer exhibits the restriction of informational suppressors normally associated with the neaA mutation (altered protein S17); ribosomes from the double mutant show increased intrinsic and neamine-induced misreading in vitro in contrast to ribosomes from the neaA strain, although still less than the misreading level of ribosomes from the ramC (altered protein S5) strain. These properties suggest that ribosomal proteins S5 and S17 act cooperatively to balance translational fidelity.