Objective
The long term aim of this proposal is to decipher the molecular mechanisms by which proteins equilibrate under the effect of a constant stretching force. We will use the newly developed single molecule force-clamp spectroscopy technique to elucidate, with exquisite sub-Ǻngström sensitivity, the dynamics of proteins as they unfold, collapse and refold in response to a mechanical force. We will first examine the conformational dynamics of a single refolding protein during its individual folding trajectory from highly extended states. In particular, we will focus on the characterization of the newly discovered ensemble of collapsed states that hold the key to explaining how an extended polypeptide folds while regaining its mechanical stability. We will expand this novel methodology to study the collapsed conformations of the amyloid forming proteins α-synuclein, which causes Parkinson’s disease, Aβ42, responsible for Alzheimer’s disease, and γD-crystallin, which triggers the cataracts in the eye lens. While current studies have mainly focused on the mechanisms of bulk aggregation and amyloid formation, an emerging consensus is that conformational diseases originate at the single molecule level, when an innocuous monomer undergoes a structural transition into a toxic β-sheet conformation. The uncanny ability of single molecule techniques to observe the acquisition of rare misfolded conformations will help establish mechanistic paradigms for developing a unified molecular scale understanding of the origins of these diseases. Finally, we will use our force-clamp assay to examine how force affects the chemical mechanisms of disulfide bond reduction in proteins exposed to mechanical forces. Within a multidisciplinary approach, here we propose a series of innovative experiments to directly probe the effect of force on the function of an individual folding polypeptide and the mechanisms by which mechanical forces modulate chemical reactions, of common occurrence in nature
Fields of science
Not validated
Not validated
Call for proposal
FP7-PEOPLE-2011-CIG
See other projects for this call
Coordinator
WC2R 2LS London
United Kingdom