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Full text release has been delayed at the author's request until December 18, 2025
ETD Abstract Container
Abstract Header
Molecular Basis of Ultrafast Catalysis by DNA Photolyase
Author Info
Chakraborty, Debanjana
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1692376595401365
Abstract Details
Year and Degree
2023, Doctor of Philosophy, Ohio State University, Biochemistry Program, Ohio State.
Abstract
Cyclobutane pyrimidine dimers (CPD) are carcinogenic DNA photolesions formed between two adjacent thymine bases in genomic DNA by UV irradiation. DNA photolyases are ancient photoenzymes that evolved to specifically recognize, bind to and repair these lesions using blue light in ultrafast timescale. Comprehensive molecular level understanding of enzymatic CPD cycloreversion is lacking. We highlight various molecular factors from both enzyme active site and substrate itself, that modulate various electron transfer (ET) and bond rearrangement steps involved in the repair photocycle and determine the overall quantum repair yield. We tracked the real time repair dynamics of carefully planned enzyme and substrate variants using femtosecond spectroscopy. We found that active site amino acids modulate solvation around the cofactor-lesion pair and influence associated ET parameters. Steric and electrostatic properties of the substrate and the enzyme active site dictate the dimer splitting yield by tuning bond cleavage and futile ET steps. Finally, we found that the photolyases have evolved to fit the lesion in a specific binding configuration to maximize electronic coupling with electron donating cofactor and selectively destabilize various intermediates to achieve modest to high repair yields.
Committee
Dongping Zhong (Advisor)
Pages
156 p.
Subject Headings
Biochemistry
;
Biophysics
;
Chemistry
Keywords
DNA damage, DNA Photolyase, Flavin, Biological electron transfer, Ultrafast catalysis, Cycloreversion
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Citations
Chakraborty, D. (2023).
Molecular Basis of Ultrafast Catalysis by DNA Photolyase
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1692376595401365
APA Style (7th edition)
Chakraborty, Debanjana.
Molecular Basis of Ultrafast Catalysis by DNA Photolyase.
2023. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1692376595401365.
MLA Style (8th edition)
Chakraborty, Debanjana. "Molecular Basis of Ultrafast Catalysis by DNA Photolyase." Doctoral dissertation, Ohio State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=osu1692376595401365
Chicago Manual of Style (17th edition)
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Document number:
osu1692376595401365
Copyright Info
© 2023, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.