1. Single-strand binding proteins DNA replication, part 2

2. Table 20.1

3. Figure 20.19 Stimulation of DNA synthesis by T4 phage SSB, gp32

4. amB17(gene23) tsP7 (gene 32), amB17(gene23) amE727 (gene 49), tsP7 (gene 32), Effect of the SSB gene 32

5. Topoisomerases

6. Rubber band model of supercoiling in DNA

7. Nicking one strand - relaxation of supercoiling

8. Problem of Strain due to Unwinding of DNA by Helicase is solved by the Swivel Concept

9. DNA gyrase is a a DNA topisomerase relaxed supercoiled

10. Topoisomerase II forms a covalent DNA-enzyme intermediate with its Tyr residues

11. Cyrstal structure of yeast DNA topoisomerase

12. Model in segment passing in topoisomerase II

13. DNA polymerases

14. Proofreading in DNA synthesis

15. DNA polI

16. Crystal structure of the Klenow fragment

18. Purification of DNA polymerases by DEAE sephacel polA1 strain Wild type with & w/o N- ethylmaleimide (blue line)

19. Separation of polIII core and alpha subunit

20. Exonuclease activity of the epsilon subunit Perfectly paired DNA substrate Imperfectly paired DNA substrate

22. Termination of DNA replication

24. Replication Leaves Catenated Daughter Chromosomes

25. Two-step Model for Decatenation in Prokaryotes

26. Cozarelli and Colleagues: Topo IV is Responsible for Decatenation in Bacteria Studied decatenation of intertwined pBR322 plasmids Used ts mutations S. typhimurium; Mutations were in gryA (encodes gyrase), parC and parE (encode two subunits of topo IV) and parF (unrelated gene linked to parC and E) Found mutations only in parC and parE (and not gyrA) prevented decatenation. Therefore, topo IV acts in decatenation. In eukaryotes topo II is the probably the decatenating enzyme.

27. The problem with replication of Linear DNA

28. Telomerase activity on four repeats of TTGGGG Tetrahymena

29. Telomeres in the protozooan Tetrahymena

30. Telomere binding proteins in ciliates and yeast