PhD defence D. (Doreth) Bhairosing-Kok
- Prof.dr. T.K. Sixma
- Dr. E. Lamers
On Friday 29 January 2021, D. Bhairosing-Kok will defend her PhD dissertation, entitled: ‘Studying the Activation States of MutS and MutL in DNA Mismatch Repair’.
DNA Mismatch repair (MMR) is a DNA repair mechanism that corrects mistakes (mismatches) in the DNA. Almost every organism has MMR and therefore this mechanism is highly conserved. For this reason, I studied MMR in the model organism Escherichia coli (E.coli). There are two MMR proteins that initiate MMR: MutS and MutL. MutS scans every piece of DNA, looking for mismatches or weaknesses in the DNA helix. When a mismatch is detected, MutS undergoes conformational changes and it recruits the next protein: MutL. MutL is a matchmaker, and it recruits other proteins after activation by MutS. During my PhD I studied the 3D structure of these proteins with cryo-Electron Microscopy. With this technique, you collect a lot of (2D) pictures of frozen proteins. When all these 2D snapshots are collected, they can be processed into a 3D density. Having a 3D structure of a protein, or protein-complex, allows us to understand the mechanism of MMR initiation. These results are shown in my dissertation.
Due to corona, the PhD defences do not take place publicly in the usual way in the Senate Hall or in the Professor Andries Querido Room. The candidates will defend their dissertation either in a small group or online.