PHILADELPHIA A protein's function depends on both the chains of molecules it is made of and the way those chains are folded. And while figuring out the former is relatively easy, the latter represents a huge challenge with serious implications because many diseases are the result of misfolded proteins. Now, a team of chemists at the University of Pennsylvania has devised a way to watch proteins fold in "real-time," which could lead to a better understanding of protein folding and misfolding in general.
The research was conducted by Feng Gai, professor in the Department of Chemistry in the School of Arts and Sciences, along with graduate students Arnaldo Serrano, also of Chemistry, and Robert Culik of the Department of Biochemistry and Molecular Biophysics at Penn's Perelman School of Medicine. They collaborated with Michelle R. Bunagan of the College of New Jersey's Department of Chemistry.
Their research was published in the international edition of the journal Angewandte Chemie, where it was featured on the cover and bestowed VIP (very important paper) status.
"One of the reasons that figuring out what happens when proteins fold is difficult is that we don't have the equivalent of a high-speed camera that can capture the process, " Gai said. "If the process were slow, we could take multiple 'pictures' over time and see the mechanism at work. Unfortunately, no one has this capability; the folding occurs faster than the blink of an eye."
Gai's team uses infrared spectroscopy a technique that measures how much light different parts of a molecule absorbs to analyze proteins' structure and how this changes. In this case, the researchers looked at a model protein known as Trp-cage with an infrared laser setup.
In this experiment, Gai's team used two lasers to study structural changes as a function of time. The first laser acts as the starting gun; by heating the molecule, it causes its structure to change. The seco
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University of Pennsylvania