Proofreading mechanisms intrinsic to DNA and RNA polymers that contribute substantially to overall fidelity are lacking in the ribosome. New evidence, however, suggests that quality control in translation can occur after substrate incorporation by an abortive mechanism entailing premature release factor-catalyzed termination. These data shed new light on the importance and ubiquity of retrospective quality control mechanisms in ensuring the overall fidelity of nature's processive enzymes and demonstrate that competitive elongation reactions on the ribosome are kinetically sensitive to compositional features of the translating particle.
