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Phys. Rev. E 69, 011912 (2004) [4 pages]

Stretching of proteins in the entropic limit

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Marek Cieplak1,2, Trinh Xuan Hoang3, and Mark O. Robbins1
1Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
2Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
3The Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34014 Trieste, Italy

Received 11 April 2003; revised 7 October 2003; published 30 January 2004

Mechanical stretching of six proteins is studied through molecular dynamics simulations. The model is Go-like, with Lennard-Jones interactions at native contacts. Low-temperature unfolding scenarios are remarkably complex and sensitive to small structural changes. Thermal fluctuations reduce the peak forces and the number of metastable states during unfolding. The unfolding pathways also simplify as temperature rises. In the entropic limit, all proteins show a monotonic decrease of the extension where bonds rupture with their separation along the backbone (contact order).

© 2004 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevE.69.011912
DOI:
10.1103/PhysRevE.69.011912
PACS:
87.15.La, 87.15.He, 87.15.Aa