Thermal unfolding of proteins is compared to folding and mechanical stretching in a simple topology-based dynamical model. We define the unfolding time and demonstrate its low-temperature divergence. Below a characteristic temperature, contacts break at separate time scales and unfolding proceeds approximately in a way reverse to folding. Features in these scenarios agree with experiments and atomic simulations on titin.

1.
H.
Abe
and
N.
Go
,
Biopolymers
20
,
1013
(
1981
).
2.
S.
Takada
,
Proc. Natl. Acad. Sci. U.S.A.
96
,
11698
(
1999
).
3.
See, e.g.,
V. S.
Pande
and
D. S.
Rokhsar
,
Proc. Natl. Acad. Sci. U.S.A.
96
,
9062
(
1999
).
4.
A. R.
Fersht
,
Structure and Mechanism in Protein Science: A Guide to Enzyme Catalysis and Protein Folding
(
New York
, Freeman,
1998
).
5.
A.
Li
and
V.
Daggett
,
Proc. Natl. Acad. Sci. U.S.A.
91
,
10430
(
1994
).
6.
S. L.
Kazmirski
,
K.-B.
Wong
,
S. M. V.
Freund
,
Y.-J.
Tan
,
A. R.
Fersht
, and
V.
Daggett
,
Proc. Natl. Acad. Sci. U.S.A.
98
,
4349
(
2001
).
7.
I.
Chang
,
M.
Cieplak
,
J. R.
Banavar
, and
A.
Maritan
,
Protein Sci.
13
,
2446
(
2004
).
8.
M.
Cieplak
and
T. X.
Hoang
,
Biophys. J.
84
,
475
(
2003
).
9.
M.
Cieplak
,
T. X.
Hoang
, and
M. O.
Robbins
,
Proteins: Struct., Funct., Bioinf.
56
,
285
(
2004
).
10.
F. C.
Bernstein
,
T. F.
Koetzle
,
G. J. B.
Williams
,
E. F.
Meyer
, Jr.
,
M. D.
Brice
,
J. R.
Rodgers
,
O.
Kennard
,
T.
Shimanouchi
, and
M.
Tasumi
,
J. Mol. Biol.
112
,
535
(
1997
).
11.
M.
Rief
,
M.
Gautel
,
F.
Oesterhelt
,
J. M.
Fernandez
, and
H. E.
Gaub
,
Science
276
,
1109
(
1997
).
12.
P. E.
Marszalek
,
H.
Lu
,
H. B.
Li
,
M.
Carrion-Vazquez
,
A. F.
Oberhauser
,
K.
Schulten
, and
J. M.
Fernandez
,
Nature (London)
402
,
100
(
1999
).
13.
S. B.
Fowler
,
R. B.
Best
,
J. L.
Toca Herrera
,
T. J.
Rutherford
,
A.
Steward
,
E.
Paci
,
M.
Karplus
, and
J.
Clarke
,
J. Mol. Biol.
322
,
841
(
2002
).
14.
S. B.
Fowler
and
J.
Clarke
,
Structure (London)
9
,
355
(
2001
).
15.
C. D.
Geierhaas
,
E.
Paci
,
M.
Vendruscolo
, and
J.
Clarke
,
J. Mol. Biol.
343
,
1111
(
2004
).
16.
M.
Cieplak
,
T. X.
Hoang
, and
M. O.
Robbins
,
Proteins: Struct., Funct., Bioinf.
49
,
114
(
2002
).
17.
M.
Cieplak
,
A.
Pastore
, and
T. X.
Hoang
,
J. Chem. Phys.
122
,
054906
(
2004
).
18.
M.
Cieplak
,
Physica A
352
,
28
(
2004
).
19.
J.
Tsai
,
R.
Taylor
,
C.
Chothia
, and
M.
Gerstein
,
J. Mol. Biol.
290
,
253
(
1999
).
20.
N. D.
Socci
and
J. N.
Onuchic
,
J. Chem. Phys.
101
,
1519
(
1994
).
21.
The relevance of this value of l also emerges in the context of the tube model of proteins, see
J. R.
Banavar
,
M.
Cieplak
, and
A.
Maritan
,
Phys. Rev. Lett.
93
,
238101
(
2004
).
22.
D.
Shortle
and
M. S.
Ackerman
,
Science
293
,
487
(
2001
).
23.
M.
Cieplak
,
T. X.
Hoang
, and
M. O.
Robbins
,
Phys. Rev. E
69
,
011912
(
2004
).
24.
M.
Doi
and
S. F.
Edwards
,
Theory of polymer dynamics
(
Oxford University Press
, Oxford,
1988
).
25.
E.
Paci
and
M.
Karplus
,
Proc. Natl. Acad. Sci. U.S.A.
97
,
6521
(
2000
).
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