Mechanical unfolding of a beta-hairpin using molecular dynamics
Single molecule mechanical unfolding experiments have the potential to provide insights into the details of protein folding pathways. To investigate the relationship between force-extension unfolding curves and microscopic events, we performed molecular dynamics simulations of the mechanical unfolding of the C-terminal hairpin of protein G. We have studied the dependence of the unfolding pathway on pulling speed, cantilever stiffness, and attachment points. Under conditions which generate low forces, the unfolding trajectory mimics the untethered, thermally accessible pathway previously proposed based on high temperature studies. In this stepwise pathway, complete breakdown of backbone hydrogen bonds precedes dissociation of the hydrophobic cluster. Under more extreme conditions, the cluster and hydrogen bonds break simultaneously. Transitions between folding intermediates can be identified in our simulations as features of the calculated force-extension curves.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Laboratory Directed Research and Development (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 767553
- Report Number(s):
- LBNL-44401; BIOJAU; R&D Project: 366827; TRN: AH200038%%404
- Journal Information:
- Biophysical Journal, Vol. 78, Issue 2; Other Information: PBD: 16 Oct 1999; ISSN 0006-3495
- Country of Publication:
- United States
- Language:
- English
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