Professor Alessandro Senes at the University of Wisconsin-Madison, USA, is supported by the Chemistry of Life Processes Program in the Division of Chemistry, for an International Collaboration in Chemistry (ICC) award that comprises an international collaboration with Professor Isiah Arkin, of The Hebrew University of Jerusalem in Israel, who is supported by The Israel Bi-national Science Foundation.
The aim of this project is to investigate one of the forces responsible for the shapes of membrane proteins. Integral membrane proteins are embedded within cellular membranes, at the boundaries between the cell and the outside environments, as well as within the membrane of intracellular compartments called organelles, where these proteins perform a wide variety of essential functions. In order to perform these functions, membrane proteins are required to fold into a defined three-dimensional structure and often associate with other membrane proteins. The forces that allow membrane proteins to fold into a particular three-dimensional structure and associate with each other are still not well understood. This research will elucidate the specific role played by one of these fundamental forces - hydrogen bonding - in the folding and association of membrane proteins. The outcomes of this proposal will be used to better understand a wide variety of important biological systems. The project will have a broader impact through research training in an interdisciplinary environment. The interdisciplinary nature of the work will provide graduate students and postdoctoral fellows, as well as early career students, with opportunities to acquire inter-disciplinary training in a variety of experimental and computational methods. In addition, a broader impact is achieved through providing high school students with computational skills and outreach efforts to inform the public of the importance of multidisciplinary research in the advancement of science.
The research in this project addresses quantitatively the important question of the contribution of hydrogen bonding to stability and interaction specificity in membrane proteins, with the use of a unique combination of advanced experimental and computational approaches. Isotope-edited FTIR spectroscopy coupled with DFT calculations will be used to analyze the specific energetics of individual hydrogen bonds in interacting transmembrane alpha-helices. In parallel, the overall thermodynamic stability of association of the same alpha-helices will be assessed by using a combination of FRET and analytical ultracentrifugation. This research will be accomplished using a structural framework provided by advanced computational modeling, initially in the context of characterized model systems, and later using predicted oligomerizing helices from single-pass membrane proteins, as well as membrane proteins of known structure. This approach will allow exploration of the relationship between the strength of individual hydrogen bonds and their effective contribution to complex formation.
