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Action Of Tyrosyl Dna Phosphodiesterase On 3'-Phosphoglycolate Terminated Dna Strand Breaks, Haritha Tatavarthi
Action Of Tyrosyl Dna Phosphodiesterase On 3'-Phosphoglycolate Terminated Dna Strand Breaks, Haritha Tatavarthi
Theses and Dissertations
Free radical-mediated DNA double strand breaks (DSBs) are induced either directly by ionizing radiation or by certain chemicals like bleomycin. These breaks are terminated by 3'-PG (PO4CH2COOˉ) or 3'-phosphate groups formed as a result of fragmentation of deoxyribose. To study the nature of repair of these 3'-blocked breaks, we constructed substrates mimicking free-radical induced DSBs. Human and yeast tyrosyl DNA-phosphodiesterase (Tdpl) efficiently processed substrates with 3'-PGs, in either the presence or absence of magnesium, to give a 3'-phosphate. Gel filtration chromatography and western blotting codmed that the putative enzyme in human extracts that efficiently processed PG was indeed tyrosyl DNA-phosphodiesterase. …