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Mechanics of forced unfolding of proteins

Paper ID Volume ID Publish Year Pages File Format Full-Text
1242 80 2009 9 PDF Available
Title
Mechanics of forced unfolding of proteins
Abstract

We describe and solve a two-state kinetic model for the forced unfolding of proteins. The protein oligomer is modeled as a heterogeneous, freely jointed chain with two possible values of Kuhn length and contour length representing its folded and unfolded configurations. We obtain analytical solutions for the force–extension response of the protein oligomer for different types of loading conditions. We fit the analytical solutions for constant-velocity pulling to the force–extension data for ubiquitin and fibrinogen and obtain model parameters, such as Kuhn lengths and kinetic coefficients, for both proteins. We then predict their response under a linearly increasing force and find that our solutions for ubiquitin are consistent with a different set of experiments. Our calculations suggest that the refolding rate of proteins at low forces is several orders larger than the unfolding rate, and neglecting it can lead to lower predictions for the unfolding force, especially at high stretching velocities. By accounting for the refolding of proteins we obtain a critical force below which equilibrium is biased in favor of the folded state. Our calculations also suggest new methods to determine the distance of the transition state from the energy wells representing the folded and unfolded states of a protein.

Keywords
Proteins; AFM; Kinetic model
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Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 5, Issue 6, July 2009, Pages 1855–1863
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us