Notes Feb 5 - Feb 5 Lecture 6 Today- Continuing Ch 24 For...

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Feb 5 Lecture 6 Today- Continuing Ch 24 For Next Lecture- Ch 25 24-8; 24-18,19,20,23; Table 24-2; 24-21; // 24-40, Table 24.3; 24-41,42,44,45,46,47,48 - Without nicks, you cant change the overall topology - How does type 1 topoisomerase works? o - Box 24-2 o Ciproflacin and Novobiciocin are bacteria drugs o Damage the DNA by preventing replication o Ciproflaxin and novobiocin specifically inhibit DNA gyrase but not eukaryotic topoisomerase II o Doxorubicin and etopside inhibit eukaryotic type II toposiomerase o Novobiocin inhibits the ATPse activity, therefore killing cells by blocking topoisomerase activity o The other drugs, doxorubicin, etopside, and ciprofloxacin enhance the rate at which type II topoisomerase cleave double stranded DNA but reduce the rate at which the breaks are sealsed o Camptothecin inhibit type IB topoisomerase by prolonging the lifetime of the covalent enzyme-DNA intermediate - Denaturing of DNA - Fig, 24-18 o Double helix are rigid rods and have high viscosity, which arises from the resistance to deformation of its rigid and rodlike duplex molecules o while the single stranded denatured DNA is a random coil that is more flexible and stretched out in solution o Extremely long for how thin it is - Fig 24-19 o Absorption spectrum of DNA native and denatured o Double stranded native DNA has less absorption than denatured o When the purine are exposed to solvent, they have different electron interaction with the UV light compared to when they are in the interior of the double helix o DNA’s u absorbance which is almost entirely due to its aromatic bases, increases by 40% on denaturation as a consequence of the disruption of the electronic interactions among neighboring bases o Single stranded DNA has higher absorbtion; the actual reason involved quantum mechanic calculations o Superficial reason o When the purine and pyramiding bases that are absorbing the light at 260 nm are exposed to solvent, they have a different electronic interaction compared to when they are less exposed
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Notes Feb 5 - Feb 5 Lecture 6 Today- Continuing Ch 24 For...

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