X-Ray Diffraction Indicates That Active Cross-Bridges Bind to Actin Target Zones in Insect Flight Muscle
نویسندگان
چکیده
منابع مشابه
In Vivo Time Resolved X-ray Diffraction Reveals Radial Motions of Myofilaments in Insect Flight Muscle
INTRODUCTION The constraint of constant volume for a contracting muscle cell implies a radial expansion that occurs during axial shortening will lead to increases in the radial spacing of the lattice of myofilaments. That change in filament spacing, in turn, can have a profound effect on the attachment rate of crossbridges [1]. At the same time, cross-bridges attaching to thin filaments and gen...
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The mode of binding of myosin subfragment-1 (S1) to actin is known to depend on their molar ratio: when actin is in excess, S1 binds to two actin monomers within the actin filament, and when S1 is in excess or is equimolar with actin, each S1 binds to one actin monomer. Since in vertebrate striated muscle actin is in molar excess over myosin, we expect that in fibers each myosin head binds to t...
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Small insects drive their flight muscle at frequencies up to 1,000 Hz. This remarkable ability owes to the mechanism of stretch activation. However, it remains unknown as to what sarcomeric component senses the stretch and triggers the following force generation. Here we show that the earliest structural change after a step stretch is reflected in the blinking of the 111 and 201 reflections, as...
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Defining the structural changes involved in the myosin cross-bridge cycle on actin in active muscle by X-ray diffraction will involve recording of the whole two dimensional (2D) X-ray diffraction pattern from active muscle in a time-resolved manner. Bony fish muscle is the most highly ordered vertebrate striated muscle to study. With partial sarcomere length (SL) control we show that changes in...
متن کاملX-ray diffraction evidence for myosin-troponin connections and tropomyosin movement during stretch activation of insect flight muscle.
Stretch activation is important in the mechanical properties of vertebrate cardiac muscle and essential to the flight muscles of most insects. Despite decades of investigation, the underlying molecular mechanism of stretch activation is unknown. We investigated the role of recently observed connections between myosin and troponin, called "troponin bridges," by analyzing real-time X-ray diffract...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 1998
ISSN: 0006-3495
DOI: 10.1016/s0006-3495(98)77856-7