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15 Cards in this Set
- Front
- Back
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A-DNA has what characteristics?
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Rt Hand. 26Å diameter, 11.6BP/turn, 31˚helical twist/BP, 34Å Helix pitch,20˚P
Major Groove: narrow and deep Minor Groove: wide and shallow |
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B-DNA has what characteristics
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Rt Hand. 20Å diameter, 10BP/turn, 36˚helical twist/BP, 34Å Helix pitch, 6˚Pitch
Major Groove: Wide and deep Minor Groove: narrow and deep |
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Z-DNA has what characteristics
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Lt Handed. 18Å diameter, 12BP/turn, 60˚helical twist/BP, 44Å Helix pitch, 7˚Pitch
Major Groove: Flat Minor Groove: narrow and deep |
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Type I topoisomerase are what
Type II topoisomerases are what |
type I act by creating Transient single breaks in DNA It can unwind by 1 turn. Type II work by making transient double strand breaks and unwinds by 2 turns and require ATP
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Type IA topoisomerase and IB differ in what
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IA can relax only negative supercoils and has a mechanism of Tyr bondind to 1 strand. IB can relax positive or negative by controlled rotation mechanism.
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Specifics for type II topoisomerase
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It can relax +- supercoils but only prok DNA gyrase can introduce negative supercoils. Active tyr residues like type I. It uses ATPase to promote cleavage of 1 strand to let the other strand pass into the inner part of the enzyme.
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Inhibitors of Type II topoisomerase:
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Ciprofloxacin(most powerful) and novobiocin inhibit DNA gyrase but not euk topo II. Camptothecin inhibit topo IB by binding to nicked strands for chemotherapy.
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Absorbance at 260nm is increased by what.
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Heating the DNA to separate the strands which deshields the aromatic heterocylic nitrogenous bases. Hyperchromic effect.
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H-bonds are weak compared to what other itneractions.
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Base stacking and hydrophobic interactions. nonpolar solvents denature DNA which is evidence of a entropically opposed stacking.
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adding monovalent cations to DNA will do what by what interactions
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Raise the melting temperature of duplex DNA by shielding the anionic phosphate groups from eachother by ionic interactions
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fractionation of NA include what steps?
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-deproteinized by phenol precip. or by guanidinium chloride or high salt or protease. Then ethanol precip for DNA and RNA. Then DNAase or RNAse. Nuclease inhibited by chelating divalent cations by EDTA
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intercalation agens are what
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ethidium ion, acridine orange and proflavin intercalate the DNA to stain it for gel run
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PFGE and EMSA is what
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pulsed field gel electrophoresis and electrophoretic mobility shift assay(protein DNA binding)
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a prokaryotic translational control motif is?
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HTH which is a repressor and binds to palendromic sequences like endonucleases. ecoli TRP repressor.
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eukarytic transcription factors include
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zinc finger with Cys2-His2, Leuc zipper and HLH dimerzation domain
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