Science Digest Chalk Talk: "Error-speed correlations in biopolymer synthesis"

Davide Chiuchiu (Postdoc at Pigolotti Unit)

Abstract:

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.

In this talk, I will show that the fluctuations in the error rate and the speed of a replicative enzyme reveal details of its error-correction mechanisms. The error and speed fluctuations in a replicative enzyme are correlated at the single-molecule level. As a consequence, the enzyme tends to yield either less or more errors than the average when thermal fluctuations speed up the synthesis. The error-correction mechanisms in the enzyme determine which of the two cases hold. For example, discrimination in the forward reaction rates tends to grant smaller errors to enzymes with higher speed. The opposite occurs for discrimination in the monomer rejection rates. Error-speed correlations thus provide a feasible way to identify error-correction mechanisms in biopolymer synthesis.