\nomenclature{I27}{Immunoglobulin-like domain 27 from human Titin}\index{I27}
I27 is a model protein that has been used in mechanical unfolding
experiments since the first use of synthetic
-chains\citep{carrion-vazquez99b,TODO}. It was used here because it is
+chains\citep{carrion-vazquez99a,TODO}. It was used here because it is
both well characterized and readily available (%
\href{http://www.athenaes.com/}{AthenaES}, Baltimore, MD,
\href{http://www.athenaes.com/I27OAFMReferenceProtein.php}{0304}).
and stiffer linkers will increase the mean unfolding force.
Unfolded I27 domains can be well-modeled as wormlike chains (WLCs,
-\cref{sec:tension:wlc})\citep{carrion-vazquez99b}, where $p \approx
+\cref{sec:tension:wlc})\citep{carrion-vazquez99a}, where $p \approx
4\U{\AA}$ is the persistence length, and $L \approx 28\U{nm}$ is the
contour length of the unfolded domain. Obviously effective stiffness
of an unfolded I27 domain is highly dependent on the unfolding force,
methods, AFM is the most widely used due to the availability of
user-friendly commercial instruments. AFM has been employed on
several types of biological macromolecules, mechanically unfolding
-proteins\citep{carrion-vazquez99b} and forcing structural transitions
+proteins\citep{carrion-vazquez99a} and forcing structural transitions
in DNA\citep{rief99} and polysaccharides\citep{rief97b}. An
AFM\index{AFM} uses a sharp tip integrated at the end of a cantilever
to interact with the sample. Cantilever bending is measured by a
than the forces required to unfold the protein when the surfaces are a
few nanometers apart. To circumvent these difficulties, globular
protein molecules are linked into polymers, which are then used in the
-AFM studies\citep{carrion-vazquez99b,chyan04,carrion-vazquez03}. When
+AFM studies\citep{carrion-vazquez99a,chyan04,carrion-vazquez03}. When
such a polymer is pulled from its ends, each protein molecule feels
the externally applied force, which increases the probability of
unfolding by reducing the free energy barrier between the native and
}
@article { carrion-vazquez99a,
+ author = MCarrionVazquez #" and "# AOberhauser #" and "# SFowler #" and "#
+ PMarszalek #" and "# SBroedel #" and "# JClarke #" and "# JFernandez,
+ title = "Mechanical and chemical unfolding of a single protein: A
+ comparison",
+ year = 1999,
+ month = mar,
+ day = 30,
+ journal = PNAS,
+ volume = 96,
+ number = 7,
+ pages = "3694--3699",
+ doi = "10.1073/pnas.96.7.3694",
+ eprint = "http://www.pnas.org/cgi/reprint/96/7/3694.pdf",
+ url = "http://www.pnas.org/cgi/content/abstract/96/7/3694"
+}
+
+@article { carrion-vazquez99b,
author = MCarrionVazquez #" and "# PMarszalek #" and "# AOberhauser #" and
"# JFernandez,
title = "Atomic force microscopy captures length phenotypes in single
proteins",
year = 1999,
+ month = sep,
+ day = 28,
journal = PNAS,
volume = 96,
number = 20,
abstract = ""
}
-@article { carrion-vazquez99b,
- author = MCarrionVazquez #" and "# AOberhauser #" and "# SFowler #" and "#
- PMarszalek #" and "# SBroedel #" and "# JClarke #" and "# JFernandez,
- title = "Mechanical and chemical unfolding of a single protein: A
- comparison",
- year = 1999,
- journal = PNAS,
- volume = 96,
- number = 7,
- pages = "3694--3699",
- doi = "10.1073/pnas.96.7.3694",
- eprint = "http://www.pnas.org/cgi/reprint/96/7/3694.pdf",
- url = "http://www.pnas.org/cgi/content/abstract/96/7/3694"
-}
-
@article { chyan04,
author = CLChyan #" and "# FCLin #" and "# HPeng #" and "# JMYuan #" and "#
CHChang #" and "# SHLin #" and "# GYang,
the pulling direction. The Monte Carlo simulation method has been
used since the first report of mechanical unfolding experiments using
the AFM%
-\citep{rief97b,rief97a,rief98,carrion-vazquez99b,best02,zinober02,jollymore09},
+\citep{rief97b,rief97a,rief98,carrion-vazquez99a,best02,zinober02,jollymore09},
but these previous implementations are neither fully described nor
publicly available.
a big-picture overview before diving into the more technical papers.
There are two main approaches to modeling protein domain unfolding under tension: Bell's and Kramers'\citep{schlierf06,dudko06,hummer03}.
-Bell introduced his model in the context of cell adhesion\citep{bell78}, but it has been widely used to model mechanical unfolding in proteins\citep{rief97a,carrion-vazquez99b,schlierf06} due to it's simplicity and ease of use\citep{hummer03}.
+Bell introduced his model in the context of cell adhesion\citep{bell78}, but it has been widely used to model mechanical unfolding in proteins\citep{rief97a,carrion-vazquez99a,schlierf06} due to it's simplicity and ease of use\citep{hummer03}.
Kramers introduced his theory in the context of thermally activated barrier crossings, which is how we use it here.
There is an excellent review of Kramers' theory in \citet{hanggi90}.