Journal ArticleDOI
Single myosin molecule mechanics: piconewton forces and nanometre steps
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A new in vitro assay using a feedback enhanced laser trap system allows direct measurement of force and displacement that results from the interaction of a single myosin molecule with a single suspended actin filament.Abstract:
A new in vitro assay using a feedback enhanced laser trap system allows direct measurement of force and displacement that results from the interaction of a single myosin molecule with a single suspended actin filament. Discrete stepwise movements averaging 11 nm were seen under conditions of low load, and single force transients averaging 3-4 pN were measured under isometric conditions. The magnitudes of the single forces and displacements are consistent with predictions of the conventional swinging-crossbridge model of muscle contraction.read more
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Achilles tendon strain energy in distance running: consider the muscle energy cost
TL;DR: Results show that during distance running the muscle energy cost is substantially higher than the strain energy release from the AT, and at all speeds and in all groups, estimated Muscle energy cost exceeded energy return.
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The Physics of Life: one molecule at a time
TL;DR: How this new field of single-molecule cellular biophysics has evolved is outlined, the key active areas of current research are discussed and where this may all lead in the near future is speculated on.
Journal ArticleDOI
Two independent switches regulate cytoplasmic dynein’s processivity and directionality
TL;DR: It is demonstrated that cytoplasmic dynein can generate a discrete power stroke as well as a processive walk in either direction; i.e., towards the plus- or towards the minus-end of a microtubule.
Journal ArticleDOI
A mutant heterodimeric myosin with one inactive head generates maximal displacement
Neil M. Kad,Arthur S. Rovner,Patricia M. Fagnant,Peteranne B. Joel,Guy G. Kennedy,Joseph B. Patlak,David M. Warshaw,Kathleen M. Trybus +7 more
TL;DR: Data show that a double-headed molecule can achieve a working stroke of ∼10 nm with only one active head and an inactive weak-binding partner, and propose that the second head optimizes the orientation and/or stabilizes the structure of the motion-generating head, thereby resulting in maximum displacement.
References
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Journal ArticleDOI
Proposed Mechanism of Force Generation in Striated Muscle
A. F. Huxley,R. M. Simmons +1 more
TL;DR: Recordings of the change in tension in striated muscle after a sudden alteration of the length have made it possible to suggest how the force between the thick and thin muscle filaments may be generated.
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Three-dimensional structure of myosin subfragment-1: a molecular motor
Ivan Rayment,Wojciech Rypniewski,Karen Schmidt-Bäse,Karen Schmidt-Bäse,Robert Smith,Diana R. Tomchick,Diana R. Tomchick,Matthew M. Benning,Donald A. Winkelmann,Gary E. Wesenberg,Hazel M. Holden +10 more
TL;DR: The three-dimensional structure of the head portion of myosin, or subfragment-1, which contains both the actin and nucleotide binding sites, is described, and this structure of a molecular motor was determined by single crystal x-ray diffraction.
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Direct observation of kinesin stepping by optical trapping interferometry
TL;DR: It is found that kinesin moves with 8-nm steps, similar to biological motors that move with regular steps.
Journal ArticleDOI
The Mechanism of Muscular Contraction
TL;DR: There is now a real possibility of solving the problem in complete detail, provided a way can be found to crystallize a recently purified globular subfragment of the myosin molecule, and some apparently paradoxical properties of the system are revealed.
Journal ArticleDOI
Bead movement by single kinesin molecules studied with optical tweezers
TL;DR: The results of this study are consistent with a model in which kinesin detaches briefly from the microtubule during a part of each mechanochemical cycle, rather than a models in whichKinesin remains bound at all times.