The experiments for this project will employ solid-state magnetic resonance methods to investigate peptide-lipid interactions. In particular, the investigators seek to understand the molecular mechanisms by which designed, anchored, membrane-spanning peptides interact with lipids and adjust their tilt or geometry in response to changes in the lipid environment. Of specific importance will be attempts to resolve recent apparent discrepancies or controversies that have arisen between the experimental results from magnetic resonance spectroscopy and the theoretical predictions from molecular dynamics simulations concerning the behavior of peptides that span lipid bilayer membranes. The experimental methods will address these timely issues by using two independent and inherently different approaches, namely methods based upon the deuterium (2H) quadrupole interaction and the nitrogen/hydrogen (15N/1H) dipole interactions. The expected results will enhance the collective understanding of protein/lipid interactions and the function of membrane proteins at the molecular level.
The project will augment a particular University of Arkansas initiative aimed toward developing a new paradigm for undergraduate science education. This HHMI funded "Studio Approach to Science Education" has been designed for innovative recruiting of new creative minds to lifelong careers dedicated to scientific discovery, while at the same time broadening the base for participation of non-traditional individuals and underrepresented groups in science. Efforts here will broaden the team research concept by including NSF-supported students working alongside and in conjunction with ongoing studio research team members. The impact of extending the novel studio/team experience will benefit society by helping to build the future scientific work force.
Intellectual Merit. The fundamental principles that govern biological signaling and information transfer need to be better understood. This project has made several advances toward understanding the links that connect protein structure and dynamics to biological function. Modest changes in the orientations and motions of membrane proteins are likely to be very important for the regulation of biological signaling, for example by means of opening or closing channels in cell membranes in the mammalian nervous system and elsewhere. We have developed and refined magnetic resonance methods for measuring the orientations and dynamics of functional helical segments of proteins in biological lipid membranes. Specifically, the methods are sensitive to changes as small as 1°-5° in the orientations of particular functional protein segments. In ongoing experiments, we are beginning to apply our methods to measure changes in the ionization states (negative charge, positive charge, or neutral) of particular protein components in biological lipid bilayer membranes. Ionization state changes and protein motions govern, for example, the opening and closing of voltage-regulated and neurotransmitter-regulated ion channels in cell membranes, to mediate signal transduction. The ability to measure ionization behavior is a key outcome of this NSF project. This outcome opens doors and defines opportunities for future research directions toward an overriding goal of understanding biological signaling. Vital results from this work have been published in eleven peer-reviewed articles in leading scientific journals that include Biochemistry, Biophysical Journal, Journal of Physical Chemistry, Journal of the American Chemical Society, and the Proceedings of the National Academy of Sciences of the United States of America. Broader Impacts. This project has actively fostered outreach to students and the general public at all levels, from elementary schools to four-year colleges to public forums. Key undertakings have included leadership and facilitation of workshops for local K-12 students, the Arkansas Protein Virtual Reality Lab, a statewide undergraduate research conference and a local Science Café.
