The Damage and Repair of DNA The molecular basis of point mutations 1. Base substitution...
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The Damage and Repair of DNA
The molecular basis of point mutations
1. Base substitution (mismatches)
transition
transversion
Two main types of DNA damage:
*point mutations
*structural changes
2. Tautomeric shift
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3. Base analogs and chemical mutagens
Gene MutationThe molecular basis of point mutations
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DNA DamageThe molecular basis of structural damage
1. Hydrolytic damage
N-glycosidic bond – very weak and easily broken
Deamination
Deamination
Depurination
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DNA DamageThe molecular basis of structural damage
2. Alkylation
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DNA DamageThe molecular basis of structural damage
3. Oxidation and Radiation
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Repairing Damages Bases
1. Mismatch repair (MMR)
Dam methylase: MutS:
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1. Mismatch repair (MMR)
Repairing Damages Bases
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2. Photoreactivation
Repairing Damages Bases
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3. Repair of alkylation
Repairing Damages Bases
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4. Base excision repair (BER)
(BER)Repairing Damages Bases
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4. Base excision repair (BER)
Repairing Damages Bases
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5. Nucleotide excision repair (NER)
Repairing Damages Bases
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DNA Repair
7. Double Strand Break Repair (DSB)
Nonhomologous End-Joining (NHEJ)
Ku
XRCC4
DNA-PKcs
Artemis
Ligase
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DNA Repair
8. Double Strand Break (DSB) repair (Homologous Recombination)
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DNA Repair8. Double Strand Break (DSB) repair (Homologous Recombination)