Fidelity of DNA Replication in Vitro
DNA is replicated with a fidelity far higher than that expected from the specificity of Watson-Crick base pairing. The overall error rate in the replication of the chromosome of Escherichia coli is only one mistake in 108–1010 nucleotides polymerised (1) yet theoretical and experimental work suggests that non-complementary base pairing occurs at a frequency of up to 10-4 – 10-5 (2). There is strong evidence that the fidelity of DNA replication is boosted by editing or proofreading mechanisms that excise errors of misincorporation (3). For example, all known prokaryotic DNA polymerases have a 3′→5′-exo-nuclease activity that is specific for the removal of mismatched nucleotides from the growing 3′-terminus during replication (4). There are also post-replicative mismatch repair systems that patrol newly replicated DNA, repairing mismatches in the daughter strand (5).
KeywordsExonuclease Activity Mismatched Nucleotide Fragment Primer Amber Mutant Daughter Strand
Unable to display preview. Download preview PDF.
- 8.Fersht, A.R. (1979) Proc. Nat. Acad. Sci. U.S.A. 76, 4946.Google Scholar
- 15.Cotes, A., Méchali, M. and Fersht, A.R., in preparation.Google Scholar
- 16.Shi, J.P. and Fersht, A.R. (1983) in preparation.Google Scholar
- 22.Fersht, A.R., Shi, J.-P. and Tsui, W.-C. (1983) J. Mol. Biol. 165, 655.Google Scholar