Force-clamp experiments reveal the free-energy profile and diffusion coefficient of the collapse of protein molecules

H. Lannon, J. S. Haghpanah, Jin Montclare, Eric Vanden Eijnden, J. Brujic

Research output: Contribution to journalArticle

Abstract

We present force-clamp data on the collapse of ubiquitin polyproteins from a highly extended state to the folded length, in response to a quench in the force from 110 pN to 5 or 10 pN. Using a recent method for free-energy reconstruction from the observed nonequilibrium trajectories, we find that their statistics is captured by simple diffusion along the end-to-end length. The estimated diffusion coefficient of ∼100 nm2 s-1 is significantly slower than expected from viscous effects alone, possibly because of the internal degrees of freedom of the protein. The free-energy profiles give validity to a physical model in which the multiple protein domains collapse all at once and the role of the force is approximately captured by the Bell model.

Original languageEnglish (US)
Article number128301
JournalPhysical Review Letters
Volume110
Issue number12
DOIs
StatePublished - Mar 22 2013

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clamps
diffusion coefficient
free energy
proteins
Polyproteins
coefficients
Ubiquitin
profiles
molecules
Proteins
bells
degrees of freedom
statistics
trajectories
Protein Domains

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Medicine(all)

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Force-clamp experiments reveal the free-energy profile and diffusion coefficient of the collapse of protein molecules. / Lannon, H.; Haghpanah, J. S.; Montclare, Jin; Vanden Eijnden, Eric; Brujic, J.

In: Physical Review Letters, Vol. 110, No. 12, 128301, 22.03.2013.

Research output: Contribution to journalArticle

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