A novel technique to study protein folding in vivo

Researchers at the University of Illinois have created an innovative new technique to study the dynamics of protein folding in real time. Martin Gruebele’s hypothesis before he developed his novel technique was that protein folding was largely influenced by its mechanical environment, and thus could not be studied properly in a simple, artificial environment. In another words, he stated that when protein folding was studied in vitro, there was only one possible outcome to the research. However, in reality, the mechanical environment in which a protein folds largely determines the ultimate outcome. Gruebele’s goal was to be able to study proteins in their natural environment, a live cell.
In order to study protein in vivo, Gruebele and his team developed a technique called Fast Relaxation Imaging, which combines fluorescence microscopy and fast temperature jumps. Fluorescence microscopy is a common tool used to take images of the inside of cells; however, one can only observe dynamics in a cell that happen over long periods of time. Since most protein folding happens on the time scale of milliseconds, fluorescence microscopy was useless in terms of tracking the dynamics of proteins. Fast temperature jump is a technique that has been used to study cellular chemical kinetics for a while. Yet, this method restricts the user to in vitro experiments, thus simplifying the mechanical environments of cells that have proven vital in terms of in influencing protein folding.
With Fast Relaxation Imaging, laser pulses are used to achieve temperature spikes inside the cell, while an inverted fluorescence microscope is utilized to observe the protein dynamics in vivo. Using this novel technique, Gruebele discovered that rates of protein folding studied in vitro differed than those studied in vivo. Overall, the thermal denaturation and folding kinetics were slower when studied in vivo. However, his results varied depending where inside the cell the protein was. Gruebele says that this heterogeneity can be attributed to the “different channels and cellular furniture that the protein might bump into.” Gruebele’s technique is the first to take this heterogeneity into account.
Using Fast Relaxation imaging, Gruebele hopes to advance research on neurological diseases such as Alzheimer’s, and Huntington’s Disease.
This article can be found at : http://www.sciencedaily.com/releases/2010/02/100228131331.htm
Oscar Carrasco-Zevallos