be aptly circumvented by the proposed approach.},
}
+@phdthesis{ benedetti12,
+ author = FBenedetti,
+ title = {Statistical Study of the Unfolding of Multimodular Proteins
+ and their Energy Landscape by Atomic Force Microscopy},
+ year = 2012,
+ address = {Lausanne},
+ affiliation = {EPFL},
+ doctoral = {EDPY},
+ pagecount = {153},
+ doi = {10.5075/epfl-thesis-5440},
+ url = {http://infoscience.epfl.ch/record/181215},
+ eprint = {http://infoscience.epfl.ch/record/181215/files/EPFL_TH5440.pdf},
+ keywords = {atomic force microscope (AFM); single molecule force
+ spectrosopy; velocity clamp AFM; Monte carlo simulations; force
+ modulation spectroscopy; energy barrier model; non kinetic methods
+ for force spectroscopy},
+ abstract = {The aim of the present thesis is to investigate several
+ aspects of: the proteins mechanics, interprotein interactions and
+ to study also new techniques, theoretical and technical, to obtain
+ and analyze the force spectroscopy experiments. The first section
+ is dedicated to the statistical properties of the unfolding forces
+ in a chain of homomeric multimodular proteins. The basic idea of
+ this kind of statistic is to divide the peaks observed in a force
+ extension curve in separate groups and then analyze these groups
+ considering their position in the force curves. In fact in a
+ multimodular homomeric protein the unfolding force is related to
+ the number of not yet unfolded modules (we call it "N"). Such
+ effect yields to a linear dependence of the most probable
+ unfolding force of a peak on ln(N). We demonstrate how such
+ dependence can be used to extract the kinetic parameters and how,
+ ignoring it, could lead to significant errors. Following this
+ topic we continue with non kinetic methods that, using the
+ resampling from the rupture forces of any peak, could reconstruct
+ the rupture forces for all the other peaks in a chain. Then a
+ discussion about the Monte Carlo simulation for protein pulling is
+ present. In fact a theoretical framework for such methodology has
+ to be introduced to understand the various simulations done. In
+ this chapter we also introduce a methodology to study the ligand
+ receptor interactions when we directly functionalize the AFM tip
+ and the substrate. In fact, in many of our experiments, we see a
+ "cloud of points" in the force vs loading rate graph. We have
+ modeled a system composed by "N" parallel springs, and studying
+ the distribution of forces obtained in the force vs loading rate
+ graph we have establish a procedure to restore the kinetic
+ parameters used. Such procedure has then been used to discuss real
+ experiments similar to biotin-avidin interaction. In the following
+ chapter we discuss a first order approximation of the Bell-Evans
+ model where a more explicit form of the potential is
+ considered. In particular the dependence of the curvature of the
+ potential on the applied force at the minimum and at the
+ metastable state is considered. In the well known Bell-Evans model
+ the prefactors of the transition rate are fixed at any force,
+ however this is not what happen in nature, where the prefactors
+ (that are the second local derivative of the interacting energy
+ with respect to the reaction coordinate in its minimum and
+ maximum) depend on the force applied. The results obtained with
+ the force spectroscopy of the Laminin-binding-protein are
+ discussed, in particular this protein showed a phase transition
+ when the pH was changed. The behavior of this protein changes,
+ from a normal WLC behavior to a plateau behavior. The analysis of
+ the force spectroscopy curves shows a distribution of length where
+ the maximum of the first prominent peak correspond to the full
+ length of the protein. However, length that could be associated
+ with dimers and trymers are also present in this
+ distribution. Later a new approach to study the lock and key
+ mechanism, using "handles" with a specific force extension
+ pattern, is introduced. In particular handles of (I27)3 and
+ (I27–SNase)3 were biochemically attached to: strept-actin
+ molecules, biotin molecules, RNase and Angiogenin. The main idea
+ is to have a system composed by "handle-(molecule A)-(molecule
+ B)-handle" where the handles are covalently attached to the
+ respective molecules and the two molecules "A and B" are attached
+ by secondary bonds. This approach allows a better recognition of
+ the protein-protein interaction enabling us to filter out spurious
+ events. Doing a statistic on the rupture forces and comparing this
+ with the statistic of the detachments of the system of the bare
+ handles, we are able to extract the information of the interaction
+ between the molecule A and B. The two last chapters are of more
+ preliminary character that the previous part of the thesis. A
+ section is dedicated to the estimation of effective mass and
+ viscous drag of the cantilevers studied by autocorrelation and
+ noise power spectrum. Usually the noise power spectrum method is
+ the most used, however the autocorrelation should give
+ approximately the same information. The parameters obtained are
+ important in high frequency modulation techniques. In fact, they
+ are needed to interpret the results. The results of these two
+ methods show a good agreement in the estimation of the mass and
+ the viscous drag of the various cantilever used. Afterwards a
+ chapter is dedicated to the discussion of the force spectroscopy
+ experiments using a low frequency modulation of the cantilever
+ base. Such experiments allow us to record the phase and the
+ amplitude shift of the modulation signal used. Using the amplitude
+ channel we managed to restore the static force signal with a lower
+ level of noise. Moreover these signals give us direct information
+ about the dynamic stiffness and the lose of energy in the system,
+ information that, using the standard technique would be difficult
+ (or even impossible) to obtain.},
+}
+
@article{ kempe85,
author = TKempe #" and "# SBHKent #" and "# FChow #" and "# SMPeterson
#" and "# WSundquist #" and "# JLItalien #" and "# DHarbrecht