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Articles 1 - 6 of 6
Full-Text Articles in Biophysics
Swinging Lever Mechanism Of Myosin Directly Shown By Time-Resolved Cryo-Em, David P. Klebl, Sean N. Mcmillan, Cristina Risi, Eva Forgacs, Betty Virok, Jennifer L. Atherton, Sarah A. Harris, Michele Stofella, Donald A. Winkelmann, Frank Sobott, Vitold E. Galkin, Peter J. Knight, Stephen P. Muench, Charlotte A. Scarfi, Howard D. White
Swinging Lever Mechanism Of Myosin Directly Shown By Time-Resolved Cryo-Em, David P. Klebl, Sean N. Mcmillan, Cristina Risi, Eva Forgacs, Betty Virok, Jennifer L. Atherton, Sarah A. Harris, Michele Stofella, Donald A. Winkelmann, Frank Sobott, Vitold E. Galkin, Peter J. Knight, Stephen P. Muench, Charlotte A. Scarfi, Howard D. White
Department of Biomedical and Translational Sciences Faculty Publications
Myosins produce force and movement in cells through interactions with F-actin1. Generation of movement is thought to arise through actin-catalysed conversion of myosin from an ATP-generated primed (pre-powerstroke) state to a post-powerstroke state, accompanied by myosin lever swing2,3. However, the initial, primed actomyosin state has never been observed, and the mechanism by which actin catalyses myosin ATPase activity is unclear. Here, to address these issues, we performed time-resolved cryogenic electron microscopy (cryo-EM)4 of a myosin-5 mutant having slow hydrolysis product release5,6. Primed actomyosin was predominantly captured 10 ms after …
Study Of Zyomogen Granule Movement Along Actin Filaments Using A Single Beam Optical Trap, Justin James Raupp
Study Of Zyomogen Granule Movement Along Actin Filaments Using A Single Beam Optical Trap, Justin James Raupp
Wayne State University Dissertations
Zymogen granules are enzymatic vesicles in the pancreas. The surface of these zymogen granules (ZGs) has several different kinds of myosin molecules, such as myosin 1c, 6, 5c, and 7b. These molecular motors may contribute to ZG transportation in cells. To understand the molecular motors involved in the vesicle trafficking, we observed the in vitro motility of purified ZGs from rat pancreas and examined the stepping behavior and force that is generated using a single beam optical trap. To be involved in trafficking, molecular motors have certain characteristics, a high duty ratio and the ability to move continuously along actin …
Dissection Of Molecular Assembly Dynamics By Tracking Orientation And Position Of Single Molecules In Live Cells, Shalin B. Mehta, Molly Mcquilken, Patrick J. La Riviere, Patricia Occhipinti, Amitabh Verma, Rudolf Oldenbourg, Amy Gladfelter, Tomomi Tani
Dissection Of Molecular Assembly Dynamics By Tracking Orientation And Position Of Single Molecules In Live Cells, Shalin B. Mehta, Molly Mcquilken, Patrick J. La Riviere, Patricia Occhipinti, Amitabh Verma, Rudolf Oldenbourg, Amy Gladfelter, Tomomi Tani
Dartmouth Scholarship
Regulation of order, such as orientation and conformation, drives the function of most molecular assemblies in living cells but remains difficult to measure accurately through space and time. We built an instantaneous fluorescence polarization microscope, which simultaneously images position and orientation of fluorophores in living cells with single-molecule sensitivity and a time resolution of 100 ms. We developed image acquisition and analysis methods to track single particles that interact with higher-order assemblies of molecules. We tracked the fluctuations in position and orientation of molecules from the level of an ensemble of fluorophores down to single fluorophores. We tested our system …
Functional Effects Of Calcium Regulation Of Thin Filaments At Single Particle Resolution, Christopher Solis-Ocampo
Functional Effects Of Calcium Regulation Of Thin Filaments At Single Particle Resolution, Christopher Solis-Ocampo
Electronic Theses and Dissertations
Heart disease is the leading cause of death in the United States. Understanding heart function at the molecular level is critical for developing of more effective treatments. In the cardiac muscle, the thin filament is composed by troponin (Tn), tropomyosin (Tm), and F-actin. It provides Ca2+-dependent regulation of contraction by modulating myosin attachment and force generation in a cooperative scheme. However, this mechanism remains unclear. To understand thin filament activation, we studied the binding and functional properties of Tn and Tm to F-actin at single particle resolution by employing fluorescence image colocalization, in vitro motility assays, and Förster resonance energy …
Mechanism Of Catch Force: Tethering Of Thick And Thin Filaments By Twitchin., Thomas M Butler, Marion J Siegman
Mechanism Of Catch Force: Tethering Of Thick And Thin Filaments By Twitchin., Thomas M Butler, Marion J Siegman
Department of Molecular Physiology and Biophysics Faculty Papers
Catch is a mechanical state occurring in some invertebrate smooth muscles characterized by high force maintenance and resistance to stretch during extremely slow relaxation. During catch, intracellular calcium is near basal concentration and myosin crossbridge cyctng rate is extremely slow. Catch force is relaxed by a protein kinase A-mediated phosphorylation of sites near the N- and C- temini of the minititin twitchin (approximately 526 kDa). Some catch force maintenance car also occur together with cycling myosin crossbridges at submaximal calcium concentrations, but not when the muscle is maximally activated. Additionally, the link responsible for catch can adjust during shortening of …
Defocused Orientation And Position Imaging (Dopi) Of Myosin V, Rolfe G. Petschek
Defocused Orientation And Position Imaging (Dopi) Of Myosin V, Rolfe G. Petschek
Faculty Scholarship
The centroid of a fluorophore can be determined within 1.5-nm accuracy from its focused image through fluorescence imaging with one-nanometer accuracy (FIONA). If, instead, the sample is moved away from the focus, the point-spread-function depends on both the position and 3D orientation of the fluorophore, which can be calculated by defocused orientation and position imaging (DOPI). DOPI does not always yield position accurately, but it is possible to switch back and forth between focused and defocused imaging, thereby getting the centroid and the orientation with precision. We have measured the 3D orientation and stepping behavior of single bifunctional rhodamine probes …