title: Direct observation of transition paths during the folding of proteins and nucleic acids.
abstract: Transition paths, the fleeting trajectories through the transition states that dominate the dynamics of biomolecular folding reactions, encapsulate the critical information about how structure forms. Owing to their brief duration, however, they have not previously been observed directly. We measured transition paths for both nucleic acid and protein folding, using optical tweezers to observe the microscopic diffusive motion of single molecules traversing energy barriers. The average transit times and the shapes of the transit-time distributions agreed well with theoretical expectations for motion over the one-dimensional energy landscapes reconstructed for the same molecules, validating the physical theory of folding reactions. These measurements provide a first look at the critical microscopic events that occur during folding, opening exciting new avenues for investigating folding phenomena.
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada.
authors.forename: Krishna
authors.initials: K
authors.lastname: Neupane
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada.
authors.forename: Daniel A N
authors.initials: DA
authors.lastname: Foster
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada.
authors.forename: Derek R
authors.initials: DR
authors.lastname: Dee
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada.
authors.forename: Hao
authors.initials: H
authors.lastname: Yu
authors.affiliation: National Institute for Nanotechnology, National Research Council, Edmonton, Alberta, T6G 2M9, Canada.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada. National Institute for Nanotechnology, National Research Council, Edmonton, Alberta, T6G 2M9, Canada. michael.woodside@ualberta.ca.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Woodside
mesh_terms: D004247:DNA / Q000737:chemistry*; D009038:Motion; D009690:Nucleic Acid Conformation; D052898:Optical Tweezers; D044367:Phase Transition; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins; D004247:DNA