Photo of Kasey Krusemark
Monday, December 5, 2022

The Purdue College of Pharmacy is pleased to honor and recognize the outstanding research and scholarship generated by our faculty each month. This month we highlight Drs. Bo Cai, former graduate student in Medicinal Chemistry and Molecular Pharmacology, and Casey Krusemark, Associate Professor of Medicinal Chemistry and Molecular Pharmacology, for their recent publication, “Multiplexed Small Molecule Ligand Binding Assays by Affinity Labeling and DNA Sequence Analysis”, which can be read in Angew Chem Int Ed Engl (January, 2022; doi: 10.1002/anie.202113515).

Conducting a high throughput screen is very expensive, and typically it is set up to discover inhibitors to just a single protein target. Cai and Krusemark developed a way to transduce the information of a potential drug molecule binding to a protein target into DNA sequence information.

The assay platform was developed that could take advantage of the power of DNA analysis techniques. A big advantage of DNA barcoding is that it allows pooled sample analysis and multiplexing, which involves the analysis of many things at the same time. In this case, a high throughput screen of five targets was conducted simultaneously. This gives an information rich view of what proteins interact with each molecule to assess its specificity.

This work provides a new way to conduct binding assays for drugs and drug-like molecules. This is something labs do in pharmaceutical research every day. Our approach offers the potential to dramatically lower the cost and provide more information when screening compounds.

“In our screen of five bromodomain targets, we found several new inhibitor molecules, which are known inhibitors to other protein classes,” said Krusemark.  “We found several protein kinase inhibitors, a HIV reverse transcriptase inhibitor, and a methyl transferase inhibitor that showed inhibition of our bromodomain targets.”

Next, the Krusemark Lab is working to improve the assay approach to be more sensitive and to allow for screening many more proteins at the same time.

This research was conducted by former graduate student Bo Cai with additional assistance from Drs. Chiwook Park and Lan Chen. The research was conducted in RHPH 440 and at the Purdue Drug Discovery Institute Chemical Genomics Facility.