Increased discrimination through successive kinetically controlled selection steps coupled to an energy-consuming reaction. Ribosomal tRNA selection includes rejection before and after GTP hydrolysis, improving fidelity beyond a single equilibrium binding comparison.
In a generic two-stage selection model with correct and incorrect dissociation rates and , the displayed error ratio increases with either common forward rate. Slow forward transitions allow rejection at both stages, approaching discrimination , but zero forward rate gives zero output. A high-yield window can instead lie between well-separated correct and incorrect rejection rates. A finite useful optimum needs a throughput or yield objective as well as an error ratio.
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Kinetic proofreading is a molecular mechanism that enhances the fidelity of biological processes, particularly in protein synthesis and DNA replication. It involves a series of kinetic steps that allow the system to discriminate between correct and incorrect substrates or interactions, thus reducing the likelihood of errors. In the context of protein synthesis, for example, kinetic proofreading refers to the way ribosomes ensure that the correct aminoacyl-tRNA is matched with the corresponding codon on the mRNA.