[21] Preparation and identification of α- and β-tropomyosins

Smillie, Lawrence B.

doi:10.1016/0076-6879(82)85023-4

Cited by 271 publications

(176 citation statements)

References 14 publications

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“…Tropomyosins are a diverse group of proteins with distinct isoforms found in muscle (skeletal, cardiac, smooth), brain and non-muscle cells. In muscles, tropomyosin interacts with actin and troponin T in regulating muscle contraction [31,32] .…”

Section: Discussionmentioning

confidence: 99%

Identification of the major allergen of Macrobrachium rosenbergii (giant freshwater prawn)

Yadzir

Misnan

Abdullah

et al. 2012

Asian Pacific Journal of Tropical Biomedicine

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Section: Discussionmentioning

confidence: 99%

Identification of the major allergen of Macrobrachium rosenbergii (giant freshwater prawn)

Yadzir

Misnan

Abdullah

et al. 2012

Asian Pacific Journal of Tropical Biomedicine

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“…TnC, TnI, and TnT were purified as described previously (15,16). Rabbit skeletal actin and bovine ventricular cardiac tropomyosin (Tm) were purified from acetone powders as described previously (34,35). Rabbit ventricular S1 was isolated from purified myosin after ␣-chymotrypsin digestion (36).…”

Section: Methodsmentioning

confidence: 99%

Engineered Troponin C Constructs Correct Disease-related Cardiac Myofilament Calcium Sensitivity

Liu

Lee

Biesiadecki

et al. 2012

Journal of Biological Chemistry

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Background: Improved myofilament Ca 2ϩ sensitivity alleviates defects in thin filament bearing disease-causing mutations. Results: By engineering the cardiac muscle Ca 2ϩ sensor troponin C, aberrant myofilament Ca 2ϩ sensitivity can be corrected in vitro. Conclusion: Engineered TnC provides a novel and versatile avenue to reset disease-related myofilament Ca 2ϩ sensitivity. Significance: Engineered TnC could be a new therapeutic strategy for cardiac muscle diseases.

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“…Actin, myosin, troponin, and tropomyosin were prepared from rabbit skeletal muscle. Tropomyosin was used as a mixture of isoforms (17). Myosin-S1 was prepared from myosin with ␣-chymotrypsin by the method of Weeds and Taylor (18) except that 2 mg of lima bean trypsin inhibitor/mg of chymotrypsin rather than phenylmethylsulfonyl fluoride was used to inhibit chymotrypsin.…”

Section: Methodsmentioning

confidence: 99%

Maximal Activation of Skeletal Muscle Thin Filaments Requires Both Rigor Myosin S1 and Calcium

Heeley

Belknap

White

2006

Journal of Biological Chemistry

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The regulation by calcium and rigor-bound myosin-S1 of the rate of acceleration of 2-deoxy-3-O-(N-methylanthraniloyl)ADP (mdADP) release from myosin-mdADP-P i by skeletal muscle thin filaments (reconstituted from actin-tropomyosin-troponin) was measured using double mixing stopped-flow fluorescence with the nucleotide substrate 2-deoxy-3-O-(N-methylanthraniloyl). The predominant mechanism of regulation is the acceleration of product dissociation by a factor of ϳ200 by thin filaments in the fully activated conformation (bound calcium and rigor S1) relative to the inhibited conformation (no bound calcium or rigor S1). In contrast, only 2-3-fold regulation is due to a change in actin affinity such as would be expected by "steric blocking" of the myosin binding site of the thin filament by tropomyosin. The binding of one ligand (either calcium or rigor-S1) produces partial activation of the rate of product dissociation, but the binding of both is required to maximally accelerate product dissociation to a rate similar to that obtained with F-actin in the absence of regulatory proteins. The data support an allosteric regulation model in which the binding of either calcium or rigor S1 alone to the thin filament shifts the equilibrium in favor of the active conformation, but full activation requires binding of both ligands.The striated muscle thin filament, a complex of five proteins (actin, tropomyosin, and troponins I, C, and T), contains an adaptable network of interactions that responds to the association with ligands (calcium and myosin) that regulate thin filament activation of myosin ATP hydrolysis. Atomic resolution structures containing the core domains of the troponin complex in the calcium-activated state and the calciumfree state have recently been reported (1, 2), but there is no high resolution structural information on ligand-induced changes that occur within a complete thin filament.Various schemes have been formulated to account for regulation. Steric blocking in its original form (3) evoked a strict competition in which tropomyosin-troponin prevented myosin binding to actin in the absence of calcium. However, steric blocking was inconsistent with subsequent observations that the effect of calcium upon the affinity of myosin for actin during steady state ATP hydrolysis is small (4). This problem was addressed by the three-state model (5), in which the thin filament can populate three conformational states with regard to myosin binding, and the modified Hill model (6), in which the thin filament primarily exists in two states. The three-state model includes a blocked state in which the myosin binding site of the thin filament is completely occluded. In the closed state the thin filament can form an initial weakly bound actomyosin complex, but the binding cannot proceed to a tightly bound rigor myosin complex. In the open state the thin filament can bind myosin tightly. An integral feature of this model is that the binding of rigor myosin locks the thin filament in the open state, which fully activates pr...

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[21] Preparation and identification of α- and β-tropomyosins

Cited by 271 publications

References 14 publications

Identification of the major allergen of Macrobrachium rosenbergii (giant freshwater prawn)

Identification of the major allergen of Macrobrachium rosenbergii (giant freshwater prawn)

Engineered Troponin C Constructs Correct Disease-related Cardiac Myofilament Calcium Sensitivity

Maximal Activation of Skeletal Muscle Thin Filaments Requires Both Rigor Myosin S1 and Calcium

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