| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophys J, December 2002, p. 3435-3445, Vol. 83, No. 6
and
*Department of Physics and Beckman Institute, University of
Illinois, Urbana, Illinois 61801 USA and
EMBL Hamburg Outstation, D-22603 Hamburg,
Germany
The cardiac muscle protein titin, responsible for
developing passive elasticity and extensibility of muscle, possesses
about 40 immunoglobulin-like (Ig) domains in its I-band region. Atomic force microscopy (AFM) and steered molecular dynamics (SMD) have been
successfully combined to investigate the reversible unfolding of
individual Ig domains. However, previous SMD studies of titin I-band
modules have been restricted to I27, the only structurally known Ig
domain from the distal region of the titin I-band. In this paper we
report SMD simulations unfolding I1, the first structurally available
Ig domain from the proximal region of the titin I-band. The simulations
are carried out with a view toward upcoming atomic force microscopy
experiments. Both constant velocity and constant force stretching have
been employed to model mechanical unfolding of oxidized I1, which has a
disulfide bond bridging 
-strands C and E, as well as reduced I1, in
which the disulfide bridge is absent. The simulations reveal that I1 is
protected against external stress mainly through six interstrand
hydrogen bonds between its A and B -strands. The disulfide bond
enhances the mechanical stability of oxidized I1 domains by restricting
the rupture of backbone hydrogen bonds between the A'- and G-strands. The disulfide bond also limits the maximum extension of I1 to ~220
Å. Comparison of the unfolding pathways of I1 and I27 are provided and
implications to AFM experiments are discussed.
Biophys J, December 2002, p. 3435-3445, Vol. 83, No. 6
© 2002 by the Biophysical Society 0006-3495/02/12/3435/11 $2.00
This article has been cited by other articles:
 |
|
 |
|
  E. H. Lee, J. Hsin, O. Mayans, and K. Schulten Secondary and Tertiary Structure Elasticity of Titin Z1Z2 and a Titin Chain Model Biophys. J., September 1, 2007; 93(5): 1719 - 1735. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. M. Toan, D. Marenduzzo, and C. Micheletti Inferring the Diameter of a Biopolymer from Its Stretching Response Biophys. J., July 1, 2005; 89(1): 80 - 86. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Lacks Energy Landscape Distortions and the Mechanical Unfolding of Proteins Biophys. J., May 1, 2005; 88(5): 3494 - 3501. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-L. Chyan, F.-C. Lin, H. Peng, J.-M. Yuan, C.-H. Chang, S.-H. Lin, and G. Yang Reversible Mechanical Unfolding of Single Ubiquitin Molecules Biophys. J., December 1, 2004; 87(6): 3995 - 4006. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Ohta, M. T. Alam, H. Arakawa, and A. Ikai Origin of Mechanical Strength of Bovine Carbonic Anhydrase Studied by Molecular Dynamics Simulation Biophys. J., December 1, 2004; 87(6): 4007 - 4020. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N.-K. Lee and D. Thirumalai Pulling-Speed-Dependent Force-Extension Profiles for Semiflexible Chains Biophys. J., May 1, 2004; 86(5): 2641 - 2649. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
