Depurination Release of adenine or guanine bases.
-
Upload
osborn-barrett -
Category
Documents
-
view
230 -
download
0
description
Transcript of Depurination Release of adenine or guanine bases.
![Page 1: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/1.jpg)
Depurination
• Release of adenine or guanine bases
![Page 2: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/2.jpg)
Deamination
• Often converts cytosine to uracil
![Page 3: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/3.jpg)
Pyrimidine Dimers
• Linkage of adjacent pyrimidine bases
![Page 4: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/4.jpg)
Summary Of DNA Damage
• hydrolysis (including depurinations and deaminations) • oxidation• methylation
![Page 5: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/5.jpg)
Replication Of Deaminated Cytosine
![Page 6: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/6.jpg)
Replication Of Depurinated Nucleotide
![Page 7: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/7.jpg)
Base Excision Repair• Remove damaged base using
DNA glycosylase• Cut phosphodiester backbone• Fill in gap
![Page 8: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/8.jpg)
Damage Detection in Deaminated DNA Bases
• Deamination leads to unnatural base, removed by DNA glycosylase
• Exception: Deamination of methylated C at CG dinucleotide generates T that is inefficiently removed
• Methylated C common site for mutation
![Page 9: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/9.jpg)
Nucleotide Excision Repair
Multienzyme complex• Recognizes bulky lesion• Cuts phosphodiester backbone
![Page 10: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/10.jpg)
Repair of Double Strand Breaks
• NHEJ: Ligation of broken ends with loss of sequence• HR: Undamaged sister chromatid as template
![Page 11: Depurination Release of adenine or guanine bases.](https://reader036.fdocuments.net/reader036/viewer/2022081513/5a4d1b4a7f8b9ab0599a5453/html5/thumbnails/11.jpg)
Diseases Of DNA Repair
Xeroderma pigmentosum
Nucleotide excision repair
UV sensitivity, skin cancer
BRCA-1, BRCA-2
Repair by homologous recombination
Breast and ovarian cancer
Hereditary nonpolyposiscolon cancer
Mismatch repair
Colon cancer
Disease Defective Process Effect