Counting cycles of EF-Tu to measure proofreading in translation.

A new method (T. Ruusala et al., 1982, EMBO J. 1, 75-78, 741-748) for analyzing kinetic proofreading in translation is described. An in vitro system is arranged so that its rate of polypeptide synthesis is determined by the release rate of GDP from EF-Tu in the absence of EF-Ts. This enables the counting of the number of EF-Tu cycles for correct as well as for incorrect peptide bonds. The necessary equations are derived and the approximations involved in these are discussed together with data from experiments not previously described.