TCB Publications - Paper Request
Mu Gao, Hui Lu, and Klaus Schulten. Unfolding of titin domains studied by molecular dynamics simulations. Journal of Muscle Research and Cell Motility, 23:513-521, 2002.
1 
m long protein found in striated muscle
myofibrils, possesses unique elastic properties. The extensible
behavior of titin has been demonstrated in atomic force
microscopy and optical tweezer experiments to involve the
reversible unfolding of individual immunoglobulin-like (Ig)
domains. We have used steered molecular dynamics (SMD), a
novel computer simulation
method, to investigate the mechanical response of single titin Ig
domains upon stress. Simulations of stretching Ig domains I1 and
I27 have been performed in a solvent of explicit water molecules.
The SMD approach provides a detailed structural and dynamic
description of how Ig domains react to external forces. Validation
of SMD results includes both quanlitative and quantitative
agreement with AFM recordings. Furthermore, combining SMD
with single molecule experimental data leads to a comprehensive
understanding of Ig domains' mechanical properties. A set of
backbone hydrogen bonds that link the domains' terminal 
-
strands play a key role in the mechanical resistance to external
forces. Slight differences in architecture permit a mechanical
unfolding intermediate for I27, but not for I1.
Refolding simulations of I27 demonstrate a locking mechanism.
