topoisomerasetypeiistructures

topoisomerasetypeiistructures内容摘要：

(via bending) • This bending provides a means to decatenation and relaxation • Preferred binding sites @ highly curved DNA crossovers and loops in vivo probably arise from intrinsic deforms DNA Berger amp。 Dong 2020 Model • Summary • Conclusions • Impact • Limitations • Comparison to Previous Models – Berger et al Model 1996 – Rybenkov et al Model 1997 – Vologodskii et al Model 2020 Berger and Dong 2020 Model Limitations • Only a portion of Topo II was examined – Fragment used was ~720 aa long (residues 4081177) • Experiment performed in vitro • Model anism used was S. cerevisiae, or yeast (is structure/binding/bending conserved with other anisms? Berger amp。 Dong 2020 Model • Summary • Conclusions • Impact • Limitations • Comparison to Previous Models – Berger et al Model 1996 – Rybenkov et al Model 1997 – Vologodskii et al Model 2020 Berger Model 1996 • One of the researchers of Dong/Berger model published a report on the Structure and Mechanism of Topo II 12 years ago • The Topo II examined was also S. cerevisiae of similar size to 2020 model • In 1996, researchers thought conformation changes occurred after passage of Tsegment, not upon binding of Gsegment • Bending of DNA upon binding with Topo II was not detected 1996 cartoon 2020 cartoon Rybenkov Model 1997 • This study didn‘t specifically look at the structure of Topo II, but it examined implications of its mechanism • Rybenkov et al concluded that Topo II doesn‘t simply catalyze the passing of one DNA strand through another, changing its local conformation and topology, but it controls the global property of DNA as well • Suggested Topo II catalyzed the passage of one strand through another if resulting crossing angles were favorable • Suggested Topo II shortened DNA • Topo II binds three (3) DNA segments (crossover plex) Top2 bound to crossover Vologodskii Model 2020 • This study attempted to use its model to explain previous experimental data • Computer Analysis of enzyme performed – Discrete wormlike chain – Monte Carlo procedure simulated possible DNA conformations – Found that simplification of DNA topology by Topo II not pos。