二DNA聚合酶与DNA的合成

二、DNA聚合酶与DNA的合成Theaccuracyoftranslationreliesonthespecificityofbasepairing.Theactualrateinbacteriaseemstobe--10-8-10-10.Thiscorrespondsto-1errorpergenomeper1000bacterialreplicationcycles,or-10-6pergenepergeneration.DNApolymerasemightimprovethespecificityofcomplementarybaseselectionateither(orboth)oftwostages:Itcouldscrutinizetheincomingbaseforthepropercomplementaritywiththetemplatebase;forexample,byspecificallyrecongnizingmatchingchemicalfeatures.Thiswouldbeapresyntheticerrorcontrol.Oritcouldscrutinizethebasepairafterthenewbasehasbeenaddedtothechain,and,inthosecasesinwhichamistakehasbeenmade,removethemostrecentlyaddedbase.Thiswouldbeaproofreadingcontrol.