Lecture 7

Question 1

DNA structure and disease

Answer 1

non B-form DNA form during DNA processes – these structures can cause DNA polymerase to stall leading to nicks and malfunctions

Question 2

topoisomerase

Answer 2

maintain proper DNA supercoiling by cutting and stitching together DNA

Question 3

B-DNA

Answer 3

base pairing, stacking, most energetically stable under physiological conditions, narrower and longer.
fits alpha-helix peptides

Question 4

A-DNA

Answer 4

observed under dehydrating conditions and high salt, compatible w/ RNA , open helical, wider and compressed – perfect for protein interactions
less solvent exposure and under dehydrating conditions and protects from these conditions
certain proteins dehydrate DNA upon binding and induce A form

Question 5

DNA is deformanble

Answer 5

structure can deviate locally when bound to small molecules
major groove binders: DNA strucutre deviates and while flanking DNA regions help retain normal structure, anitbiotic and antiviral interacts w/ sugars and edge of the bases giving seqeunce binding

Question 6

interalators: hydrophobic/hyrophillic agents that insert between bases through ring

Answer 6

hydrophobic/hyrophillic agents that insert between bases through ring stacking
ex - toto is flourescent label to detect dsDNA
interacalating as drugs: interfere w/ DNA replication, trans, repair – structural distortions lead to mutations and intercalating agents called mutagens