In the new study, Kelly's team aimed to selectively tag only the folded and functional conformations of a protein-of-interest. In one case, to demonstrate proof-of-principle, the scientists employed a model protein, retroaldolase, a designed enzyme created by collaborator David Baker's laboratory at the University of Washington, Seattle. The team also used transthyretin (TTR), a protein whose misfolding and aggregation is known to lead to several fatal disorders, including cardiomyopathies and polyneuropathies. (The Kelly laboratory recently helped develop the first specific drug therapy for the TTR polyneuropathies.)
The teamparticularly the three lead authors, graduate students Yu Liu and Yun Lei Tan and Research Associate Xin Zhangaccomplished the tagging reaction by designing and making "folding probes" that covalently labeled the properly folded, functional forms of the proteins, but not the misfolded forms. When the scientists added a solution of probe molecules to the soluble contents of cells containing the target proteins, they were able to quantify the folded target proteins from the light emitted by the probes' fluorescent beacons.
Toward Better Screens for New Drugs
Probes that covalently react with folded and functional protein families have been devised before by the Cravatt lab at TSRI. However, their usefulness as folding probes had been questioned by the scientific community, because the very act of reacting a folding probe with a target folded and functional protein-of-interest stabilizes that state and usually increases the population of the folded and functional fraction, overrepresenting it. In the new st
|Contact: Mika Ono|
Scripps Research Institute