Single molecule Förster/fluorescence resonance energy transfer (smFRET) is uniquely capable of investigating the molecular mechanisms of biological pathways that involve multiple transient protein-protein and protein-nucleic acid interactions. The first part of this talk will focus on the use of smFRET to explore the DNA mismatch repair pathway (MMR), which is a post-replicative system of enzymes that corrects rare mistakes in the genome of all organisms. Failures in the mismatch repair pathway likely initiate tumorigenesis, but currently we lack a fundamental understanding of the MMR process. The molecular mechanism of mismatch repair is critical for revealing how mutants fail to repair and may provide a basis for identifying therapeutic strategies. They utilized a combination of protein and nucleic acid fluorescent labeling strategies to monitor the dynamic interactions involved in the pathway from different vantage points. They connected the measurements via kinetic analyses to reveal coordinated conformational changes that are likely necessary for repair to commence. The techniques outlined are broadly applicable to many essential biological pathways.

The second part of this talk will focus on utilizing time-resolved confocal microscopy to achieve single molecule Fluorescence Lifetime Imaging Microscopy – FRET (FLIM-FRET). Dr. LeBlanc started her lab at NC State in Fall 2020, and they are just beginning to explore the capabilities of their new microscope to answer emerging questions.