DNA polymerase has entry site available PPP OH 13.4 DNA polymerases 5P日P OH3 control the fidelity of replication Nucleotide enters and forms bond 3'OH 3h画 eH是品PB Figure 13.6 Bacterial DNA Enzyme advances 1 nucleoli de polymerases scrutinize the 5 PPPPP 3OH base pair at the end of the growing chain and excise the nucleotide added in the case Mismatch causes removal of nucleotide enzyme retreats 1 bp of a misfit 5is388 消当
Figure 13.6 Bacterial DNA polymerases scrutinize the base pair at the end of the growing chain and excise the nucleotide added in the case of a misfit. 13.4 DNA polymerases control the fidelity of replication
13.3 DNA polymerases have various nuclease activities 53 LLL5" Nick generates 3-OH, 5-P groups 3HHHHHHHHHHHHHHHHHHHHHHH+ 5 DNA synthesis extends 3'end, old strand is degraded ◆◆OH Figure 13.5 Nick translation replaces part of a pre-existing strand of duplex DNA with newly synthesized material 消当
Figure 13.5 Nick translation replaces part of a pre-existing strand of duplex DNA with newly synthesized material. 13.3 DNA polymerases have various nuclease activities
13.3 DNA polymerases have various nuclease activities Table 15.1 Proofreading reduces the errors made by DNA polymerases Enzyme Locations of synthetic Error rate proofreading domains proofreading proofreading E coli DNA polymerase single subunit 10 5x10 E.co∥ DNA polymeraseⅢl separate subunits 7X10 5x10 -9 T4 DNA polymerase single subunit 5x10 5 7 T7 DNA polymerase unknown 10 5 10-6 Reverse transcriptase none 105 消当
13.3 DNA polymerases have various nuclease activities
13.3 DNA polymerases have various nuclease activities Table 15.2 There are 5 mammalian DNA polymerases(identified by Greek letters, yeast equivalents are given Roman numerals) DNA Polymerase a(D) 6(1) (I) Location Nuclear Nuclear Nuclear Nuclear Mitochondrial Synthetic function Priming DNA synthesis epaIr Repair Replication Other functions 3-5' exonuclease 3-5 exonuclease 3-5 exonuclease Inhibitors aphidicolin aphidicolin aphidicolin dideoxy-TTP dideoxy-TTP 消当
13.3 DNA polymerases have various nuclease activities
p dymerases cannot niti ut a prime on dup le x or sngle-strande d A 13.8 Priming is required to start ↓ HHHHHHHH DNA Synthesis 353 RNA prm er is synthe sized by base pairi ng) DNA Figure 13.12 There are 霜唱器别 several methods for providing the free 3 OH end that DNA 5 3晶 polymerases require to rimi ng nu cleat de vide d b a p rot ein tha t bind s to DNA Initiate DNA synthesis 消当
Figure 13.12 There are several methods for providing the free 3 - OH end that DNA polymerases require to initiate DNA synthesis. 13.8 Priming is required to start DNA synthesis