Employing thermal protein unfolding to search for new drugs

Finding drugs and chemicals that interact with specific proteins can be an arduous task. The list of possible compounds is nearly endless, and testing even a few with a given protein can be extremely labor intensive. One way to speed up this process is with thermal unfolding, which can quickly and simultaneously evaluate interactions with multiple compounds.

Thermal unfolding methods are built upon a simple concept: heating a protein causes it to unfold. At equilibrium, the ratio of folded to unfolded proteins in a sample is a function of temperature. A chemical binding to the protein in its folded state stabilizes it and changes the equilibrium at higher temperatures in a measurable way.

Llowarch et al. discussed the benefits of using thermal unfolding in drug discovery and highlighted promising new measurement techniques and methods.

“Thermal unfolding methods do not require a functional activity to identify binders, and so are relatively rapid and easy to develop,” said author Geoffrey Holdgate. “They can even be applied where obtaining purified protein is difficult. As a result, these methods are increasingly being used to identify start points for further chemical optimization.”

The authors point out that challenges still exist in the field. Some compounds react in unpredictable ways, appearing to destabilize proteins they interact with or interfere with detection methods, generating anomalous or misleading results.

“However they occur, understanding the nature of destabilizing compounds will be important,” said Holdgate. “I am looking forward to advances that enable us to characterize this type of behavior more effectively.”

Source: “Thermal unfolding methods in drug discovery,” by Poppy Llowarch, Laura Usselmann, Delyan Ivanov, and Geoffrey Allan Holdgate, Biophysics Reviews (2023). The article can be accessed at https://doi.org/10.1063/5.0144141 .