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2、aHyN)effictG)ndii)talfethalueduxdOfydien5-3ewnucfeaseaffictedThe accuracy of translation relies on the specificity of base pairing. The actual rate in bacteria seems to be -10-8-10-10. This corresponds to -1 error per genome per 1000 bacterial replication cycles, or -10-6 per gene per generation.DNA
3、 polymerase might improve the specificity of complementary base selection at either (or both) of two stages:It could scrutinize the incoming base for the proper complementarity with the template base; for example, byspecifically recongnizing matching chemical features. This would be a presynthetic e
4、rror control.Or it could scrutinize the base pair after the new base has been added to the chain, and, in those cases in which a mistake has been made, remove the most recently added base. This would be a proofreading control.Table 19.2 Proofreading reduces the errors made by DNA pdymBrases.EnzymeSy
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