Proofreading (biology)

The term proofreading is used in genetics to refer to the error-correcting processes, first proposed by John Hopfield and Jacques Ninio, involved in DNA replication, immune system specificity, and enzyme-substrate recognition among many other processes that require enhanced specificity.

The proofreading mechanisms of Hopfield and Ninio are non-equilibrium active processes that consume ATP to enhance specificity of various biochemical reactions.

In eukaryotes, only the polymerases that deal with the elongation (delta and epsilon) have proofreading ability (3’ → 5’ exonuclease activity).

Temperature-sensitive (ts) gene 43 mutants have been identified that have an antimutator phenotype, that is a lower rate of spontaneous mutation than wild type.

When phage T4 virions with a wild-type gene 43 DNA polymerase are exposed to either ultraviolet light, which introduces cyclobutane pyrimidine dimer damages in DNA, or psoralen-plus-light, which introduces pyrimidine adducts, the rate of mutation increases.