How Do Quadruplexes Help Proteins Fold?

Protein aggregation is the underlying cause of neurodegenerative disorders like Alzheimer’s, Huntington’s, and Parkinson’s disease. Certain proteins have been found to prevent aggregation or promote folding; these are called chaperones. The Horowitz lab has shown through research with G-quadruplexes that these nucleic acids act as chaperones to decrease protein aggregation and appear to promote folding due to their structure. Based on these previous findings we looked deeper at how chaperone impacts folding structure. CD experiments showed that G-quadruplexes were able to help proteins not misfold when heated. This is a critical part in understanding how these diseases occur and can be prevented in the future. During the CD experiments, the proteins that were combined with G-quadruplex only unfolded partially, compared to fully unfolding without the G-quadruplexes. Once they were heated, CD spectra were also taken during the cooling process. From these initial experiments, we found that two proteins when combined with a certain G-quadruplex were able to reform a greater degree of structure upon cooling to room temperature. These quadruplexes will be used for further research that looks into measuring their folding through activity assays. We will be focusing on the two proteins that showed the highest amount of recovered structure after heating. For a protein to be functional it needs to be in its native state. The activity assays will be able to
determine how much of the protein is active and functional after heating.