Error-speed correlations in biopolymer synthesis*

The synthesis of DNA and RNA requires high precision to ensure cell survival. The replicative enzymes which synthesize DNA and RNA achieve such high precision by implementing multiple error-correction mechanisms. Some of these error-correction mechanisms are not yet fully understood because of the large number of biochemical steps in DNA and RNA synthesis.
We show here that the fluctuations in the error rate and the speed of a replicative enzyme can reveal details of its error-correction mechanisms. For example, replicative enzymes that discirminate between different monomers in the forward reaction rates tends to yield polymers with less error when thermal fluctuations randomly speed up the synthesis. The opposite occurs for enzymes that discriminate between different monomers only in the rejection rates. Error-speed correlations thus provide a feasible way to identify error-correction mechanisms in biopolymer synthesis.