Thesis
Time lapsed X-ray crystallography of DNA polymerase ι
University of Iowa
Master of Science (MS), University of Iowa
Summer 2020
DOI: 10.17077/etd.005518
Abstract
When DNA becomes damaged, it creates a problem for normal DNA replication. Fortunately, the cell has pathways available to bypass the damaged DNA and continue DNA replication. One of these available pathways is called translesion synthesis (TLS). TLS uses specialized Y-family DNA polymerases to insert a nucleotide across from the site of damaged DNA. One of these Y-family polymerases is DNA polymerase iota (pol ι). Pol ι is different from other DNA polymerases because it uses Hoogsteen base pairs instead of Watson-Crick base pairs. Hoogsteen base pairing uses purines in the syn-conformation instead of the anti-configuration. Time-lapsed X-ray crystallography was used to investigate the nucleotide incorporation reaction of pol ι. A non-damaged template adenine with an incoming deoxythymidine triphosphate (dTTP) was used. Two structures were solved, a ternary substrate complex structure and a product complex structure. The ternary substrate complex structure consists of pol ι, DNA, and dTTP. The product complex structure consists of pol ι and the DNA with the dTTP incorporated. Changes in the template adenine and the active site residues in these structures were observed. The most substantial structural change is seen in the side chain of residue K309. This change provides space for the template adenine to change conformations and allow for pol ι to translocate along the DNA. These data provide insight into how pol ι accommodates and incorporates nucleotides. With these data, structure-based drug discovery can be done to create an inhibitor for pol ι.
Details
- Title: Subtitle
- Time lapsed X-ray crystallography of DNA polymerase ι
- Creators
- Devin T. Reusch
- Contributors
- Ernesto Fuentes (Advisor)Brandon Davies (Committee Member)Kris DeMali (Committee Member)Al Klingelhutz (Committee Member)Madeline Shea (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Biochemistry
- Date degree season
- Summer 2020
- DOI
- 10.17077/etd.005518
- Publisher
- University of Iowa
- Number of pages
- viii, 63 pages
- Copyright
- Copyright 2020 Devin T. Reusch
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 55-60).
- Public Abstract (ETD)
Ultraviolet and ionizing radiation, as well as several chemical agents, damage our DNA. This DNA damage creates a problem for normal DNA replication, which can lead to cancer and other diseases. Fortunately, our cells have ways to deal with this DNA damage. One of these ways the cell can deal with damaged DNA is to use translesion synthesis (TLS).
Proteins, called polymerases, replicate our DNA. However, when our DNA is damaged, normal polymerases cannot replicate through the damage. TLS uses specialized polymerases that differ from normal polymerases in that they can replicate through, but not repair, damaged DNA. One of these specialized polymerases is DNA polymerase iota (pol ι).
Pol ι is unique because it changes the structure of DNA when replicating it. My results show these expected structural changes in the DNA. More importantly, my results also show structural changes in the structure of pol ι when replicating DNA. These changes provide information on how pol ι replicates DNA and aids our understanding of how pol ι works. Understanding how pol ι works can lead to finding a pol ι inhibitor. Inhibiting pol ι may provide more effective cancer treatments since cancer cells show an increase in pol ι when exposed to chemotherapeutics.
- Academic Unit
- Biochemistry and Molecular Biology
- Record Identifier
- 9983988098402771
Metrics
11 File views/ downloads
58 Record Views