Single Molecule Studies of Tau Conformations and Dynamics

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As a growing number of proteins are identified as intrinsically disordered--consisting entirely of or containing long stretches of regions that do not populate well-defined secondary or tertiary structures--there is a corresponding growth in interest in these proteins. They challenge the central dogma in modern structural biology that function follows from structure. Gaining an understanding of how biological function is achieved is challenging in disordered proteins, in part due to the fact that they are inherently heterogeneous with multiple conformations and species populated simultaneously and with different lifetimes. In contrast to traditional ensemble methods, the single molecule biophysical approaches used in this research are uniquely suited to characterize heterogeneous molecular species in a wide range of solution conditions and associated with relevant binding partners. This project focuses on the protein tau, a microtubule binding protein that is entirely disordered in solution and only partly structured when functionally bound to microtubules. In a systematic study using single molecule experimental and computational approaches, functional fragments of tau--such as the microtubule-binding domain--will be characterized both independently of and in the context of the entire protein chain. This will allow for a precise determination how the conformations and dynamics of specific regions are coordinated, as engineered perturbations to one region of the protein will be assayed for their effects on the functionality of distant regions. Furthermore, the studies described here may serve as a model for designing studies of other intrinsically disordered proteins, and help elucidate how transient structure formation and long range interactions generate function in this intriguing group of proteins.There are a number of educational and outreach activities that are integral to the PI's research goals. The PI actively works to involve undergraduate students in research. The research projects are ideal for undergraduate research; several undergraduate students are already actively involved, including one from a summer program for underrepresented minorities, and another who will spend the summer and complete her senior thesis in the PI's lab in the upcoming year. Another component is the PI's effort in the recruitment of underrepresented students to graduate study in the sciences at Yale. In addition to serving on the departmental diversity committee, the PI has attended and spoken at conferences aimed at these minority students, including the Annual Biomedical Research Conference for Minority Students (ABRCMS) and the Conference for Undergraduate Women in Physics at Yale. Lastly is a multifaceted plan to improve interdisciplinary training opportunities for students interested in biophysical science. This includes the development and expansion of a course designed to teach mathematical methods to biology undergraduate and graduate students. The course covers analytical and numerical methods needed for analyzing biological data, with a strongemphasis on learning to use MATLAB software for solving and modeling complex biological problems. Synergistic with this course development, the PI is involved with a new training program in Biological Physics that recruits talented graduate students with an interest in interdisciplinary research, but lacking the academic training in biology or physics.