Virginia Tech
Photolyase: Its Damaged DNA Substrate and Amino Acid Radical Formation During Photorepair
Abstract
dc:description.abstractUltraviolet light damages genomic material by inducing the formation of covalent bonds between adjacent pyrimidines. Cis-syn cyclobutane pyrimidine dimers (CPD)constitute the most abundant primary lesion in DNA. Photolyase, a light-activated enzyme, catalytically repairs these lesions. Although many steps in the photolyase-mediated repair process have been mapped, details of the mechanism remain cryptic. Difference FT-IR spectroscopy was employed to obtain new mechanistic information about photorepair. Purified oligonucleotides, containing a central diuracil, dithymidine, or cyclobutane thymidine dimer, were monitored using vibrational methods. Construction of difference infrared data between undamaged and damaged DNA permitted examination of nucleic acid changes upon formation of the CPD lesion; these experiments indicated that C=O and C-H frequencies can be used as markers for DNA damage. Furthermore, in purified photolyase containing isotopically-labeled aromatic amino acids, we observed that tryptophan residues in photolyase underwent structural changes during photorepair. These data indicate that electron transfer during DNA repair occurs through-bond, and that redox-active, aromatic residues form the pathway for electron transfer.
Degree
thesis:*- Name thesis:degree_name
- Master of Science
- Level thesis:degree_level
- masters
- Discipline thesis:degree_discipline
- Biochemistry
- Department dc:contributor.department
- Biochemistry
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2005
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Hurley, E. Kenneth
- Chair dc:contributor.committeechair
-
- Kim, Sunyoung
- Committee members dc:contributor.committeemember
-
- Phillips, John B.
- Bevan, David R.
- Kennelly, Peter J.
Subjects
dc:subject × 4Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- etd-01312005-145858
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/31084