Molecular Dynamics Simulation of the α -Helix to β -Sheet Transition in Coiled Protein Filaments: Evidence for a Critical Filament Length Scale
Year: 2010
Type: article
Abstract: The alpha-helix to beta-sheet transition ($\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\ensuremath{\beta}$ transition) is a universal deformation mechanism in alpha-helix rich protein materials such as wool, hair, hoof, and cellular proteins. Through a combination of molecular and theoretical modeling, we examine the behavior of alpha-helical coiled-coil proteins with varying lengths under stretch. We find that the occurrence of the $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\ensuremath{\beta}$ transition is controlled by the length of constituting alpha-helical proteins. In the asymptotic limit, short proteins with less than 26 amino acids or 3.8 nm length reveal interprotein sliding, whereas proteins with greater lengths feature an $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\ensuremath{\beta}$ transition, leading to a significant increase in the protein's stiffness, strength, and energy dissipation capacity at large deformation. Our study elucidates the fundamental physics of this mechanism and explains why the $\ensuremath{\alpha}\mathrm{\text{\ensuremath{-}}}\ensuremath{\beta}$ transition typically occurs in protein filaments with long alpha-helical domains.
Source: Physical Review Letters
Authors: Zhao Qin, Markus J. Buehler
Institution: Massachusetts Institute of Technology
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2996377354