Transient Partial Unfolding in Proteins

Purdue University, West Lafayette IN

Investigators

Abstract

Proteins are dynamic molecules. Under native conditions, protein molecules are in thermodynamic equilibrium with transiently unfolded conformations. Understanding the nature of this transient unfolding event is one of the central questions in protein biophysics. Structures of partially-unfolded conformations transiently populated under native conditions provide important clues in elucidating protein folding mechanisms. Information on transient partial unfolding is also critical in understanding the mechanisms of protein aggregation, misfolding, and degradation. The intellectual merit of this project is to investigate the rare but critical events of transient partial unfolding proteins undergo in native conditions to further the understanding of how conformation energy landscapes control function and regulation. The specific research objectives are (1) to test the cooperativity of alpha-helix unfolding in the context of a folded protein under native conditions, (2) to test if transient partial unfolding in bacterial periplasmic proteins is a consequence of the conformational energy landscapes optimized for vectorial folding during translocation, and (3) to engineer robust proteins by utilizing information on transient partial unfolding. The broader impact of this project is education and training of graduate and undergraduate students on the principles of molecular biophysics and their application to real-world problems. First, through participation in this project, graduate and undergraduate students will have a valuable opportunity to learn the basic principles of protein biophysics and biochemistry. Students will be trained in protein engineering, protein expression and purification, and biophysical characterization of proteins through hands-on experience. Second, the results and ideas generated by this project will be directly applied to the development of a new course on biotechnological applications of proteins and peptides. The conformational equilibrium of protein structures, including protein folding, is an excellent topic to expose students to the basic principles of thermodynamics and kinetics and their applications to practical problems. Moreover, findings from this project will provide students with vivid examples of the relevance of protein conformations to practical challenges in the development and application of protein products.