Structural Kinetics of Troponin during Activation of Skeletal Muscle Fibers by Photolysis of Nitrophenyl-EGTA (NP-EGTA)
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چکیده
منابع مشابه
Activation kinetics of skinned cardiac muscle by laser photolysis of nitrophenyl-EGTA.
The kinetics of Ca(2+)-induced contractions of chemically skinned guinea pig trabeculae was studied using laser photolysis of NP-EGTA. The amount of free Ca(2+) released was altered by varying the output from a frequency-doubled ruby laser focused on the trabeculae, while maintaining constant total [NP-EGTA] and [Ca(2+)]. The time courses of the rise in stiffness and tension were biexponential ...
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Time-resolved changes in the conformation of troponin in the thin filaments of skeletal muscle were followed during activation in situ by photolysis of caged calcium using bifunctional fluorescent probes in the regulatory and the coiled-coil (IT arm) domains of troponin. Three sequential steps in the activation mechanism were identified. The fastest step (1,100 s(-1)) matches the rate of Ca(2+)...
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In glycerol-treated sartorius muscle fibres, membranes were depolarized to about-30 mV when muscle fibres were perfused with Ca-free solution containing 2 mM EGTA. Under such a condition, muscle fibres were able to produce not only an initial spike potential (initial SP) but also a following slow depolarizing response (slow DR) forming a plateau phase by cathodal current pulse when membrane was...
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Sarcoplasmic reticulum (SR) Ca release was studied at 13-16 degrees C in cut fibers (sarcomere length, 3.4-3.9 microns) mounted in a double Vaseline-gap chamber. The amplitude and duration of the action-potential stimulated free [Ca] transient were reduced by equilibration with end-pool solutions that contained 20 mM EGTA with 1.76 mM Ca and 0.63 mM phenol red, a maneuver that appeared to marke...
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Three manifestations of excitation-contraction (E-C) coupling were measured in cut skeletal muscle fibers of the frog, voltage clamped in a double Vaseline gap: intramembrane charge movements, myoplasmic Ca2+ transients, and changes in optical transparency. Pulsing patterns in the presence of high [EGTA] intracellularly, shown by García et al. (1989. J. Gen. Physiol. 94:973-986) to deplete Ca2+...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2012
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2011.11.1263