Hannover, Universiẗat, Diss., 2003.

Several key flexure sites exist in the muscle crossbridge including the actomyosin binding site which play important roles in the actomyosin crossbridge cycle. To distinguish between these sources of flexibility, a new single molecule assay was developed to observe the swiveling of rod about a single myosin. Myosins attached through a single crossbridge displayed mostly similar torsional characteristics compared to myosins attached through two crossbridges, which indicates that most of the torsional flexibility resides in the myosin subfragment-2, and thus the hinge between subfragment-2 and light meromyosin should contribute the most to this flexibility. The comparison of torsional characteristics in the absence and presence of ADP demonstrated a small but significant increase in twist rates for the double-headed myosins but no increase for single-headed myosins, which indicates that the ADP-induced increase in flexibility arises due to changes in the myosin head and verifies that most flexibility resides in myosin subfragment-2.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 4 uppsatser.

Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed January 22, 2009) Includes bibliographical references (p. 34-40).

Universiẗat, Diss., 2000--Kaiserslautern.

No description available.

Theses (Ph. D.)--Marshall University, 2007. / Title from document title page. Includes abstract. Document formatted into pages: contains xiii, 124 pages including illustrations. Includes vitae. Bibliographical references at the end of Chapters 1-3.

University, Diss., 2001--Dortmund.

No description available.

A fundamental yet unresolved issue in cell biology is how force regulates actin dynamics and how this biophysical regulation is modulated by biochemical signaling molecules. Here we show, by atomic force microscopy (AFM) force-clamp experiments, that tensile force regulates the kinetics of G-actin/G-actin and G-actin/F-actin interactions by decelerating dissociation at low forces (catch bonds) and accelerating dissociation at high forces (slip bonds). The catch bonds can be structurally explained by force-induced formation of new interactions between actin subunits (Steered molecular dynamics (SMD) simulations performed by Dr. Jizhong Lou, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China). K113S mutation on yeast actin suppressed the actin catch-slip bonds, supporting the structural mechanism proposed by SMD simulations. Moreover, formin controlled by a RhoA-mediated auto-inhibitory module can serve as a "molecular switch", converting the catch-slip bonds to slip-only. These results imply anisotropic stability of the actin network in cells subjected to directional forces, possibly explaining force-induced cell and actin fiber alignment controlled by RhoA and formin. Our study suggests a molecular level crosstalk mechanism bridging the actin-mediated mechanotransduction and biochemical signal transduction pathways.