13.5 Some DNA polymerases have a common structure Figure 13.7 Crystal structure of phage T7 DNA polymerase has a right hand structure.DNA lies across the palm and is held by the fingers and thumb Photograph kindly provided by Charles Richardson and Examcleas domain Tom Ellenberger. 清菜大当
Figure 13.7 Crystal structure of phage T7 DNA polymerase has a right hand structure. DNA lies across the palm and is held by the fingers and thumb. Photograph kindly provided by Charles Richardson and Tom Ellenberger. 13.5 Some DNA polymerases have a common structure
13.5 Some DNA polymerases have a common structure Fingers Thumb Template end of DNA is distorted Palm Exonuclease Figure 13.8 The catalytic domain of a DNA polymerase has a DNA-binding cleft created by three subdomains.The active site is in the palm.Proofreading is provided by a separate active site in an exonuclease domain 清菜大当
Figure 13.8 The catalytic domain of a DNA polymerase has a DNA-binding cleft created by three subdomains. The active site is in the palm. Proofreading is provided by a separate active site in an exonuclease domain. 13.5 Some DNA polymerases have a common structure
13.6 DNA synthesis is semidiscontinuous Lagging strand of DNA must grow overall in the 3'-5' direction and is synthesized discontinuously in the form of short fragments (5'-3)that are later connected covalently Leading strand of DNA is synthesized continuously in the 5'- 3' direction. Okazaki fragments are the short stretches of 1000-2000 bases produced during discontinuous replication:they are later oined into a covalently intact strand Semidiscontinuous replication is mode in which one new strand is synthesized continuously while the other is synthesized discontinuousl 清菜大当
Lagging strand of DNA must grow overall in the 3′-5′ direction and is synthesized discontinuously in the form of short fragments (5′-3′) that are later connected covalently. Leading strand of DNA is synthesized continuously in the 5′- 3′ direction. Okazaki fragments are the short stretches of 1000-2000 bases produced during discontinuous replication; they are later joined into a covalently intact strand. Semidiscontinuous replication is mode in which one new strand is synthesized continuously while the other is synthesized discontinuously. 13.6 DNA synthesis is semidiscontinuous
13.6 DNA synthesis is semidiscontinuous Lagging strand synthesis Prev ious fragment Last fragment Single strand P arental DNA 3 3 Leading strand. H开 5' 3TTTTTTTTTTTTTTTTTTTTTTTTTTTL Leading strand synthesis Nucleotides added continuously to 3'end Figure 13.9 The leading strand is synthesized continuously while the lagging strand is synthesized discontinuous 清苇大当
Figure 13.9 The leading strand is synthesized continuously while the lagging strand is synthesized discontinuously. 13.6 DNA synthesis is semidiscontinuous
13.7 Single-stranded DNA is needed for replication SSB is the single-strand protein of E.coli,a protein that binds to single-stranded DNA 清菜大学
SSB is the single-strand protein of E. coli, a protein that binds to single-stranded DNA. 13.7 Single-stranded DNA is needed for replication