Subunit structure and biological activity of tropomyosin B from different muscle types

Cummins, Peter L.; Perry, S. V.

doi:10.1042/bj1280106pb

Cited by 18 publications

(9 citation statements)

References 10 publications

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“…Tropomyosin is the shortest fibrous protein of this structure. It is always associated with filamentous actin, even in thin filaments that do not convey Ca 2 + sensitivity as in molluscan muscle (97,98). There is only one report claiming the occurrence of tropomyosin-free actin, in intestinal brush-border cells (72), but no conclusive evidence has been given that tropomyosin was not lost during the actin preparation procedure.…”

Section: Tropomyosinmentioning

confidence: 94%

Proteins of Contractile Systems

Mannherz¹,

Goody²

1976

Annu. Rev. Biochem.

178

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Section: Tropomyosinmentioning

confidence: 94%

Proteins of Contractile Systems

Mannherz¹,

Goody²

1976

Annu. Rev. Biochem.

178

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“…Tropomyosin was extracted from acetone powder from rabbit skeletal back muscle mince in 1.0 M KCl, 0.5 mM DTT at pH 7 according to a modified protocol of Bailey and further purified as α,α- and α,β-tropomyosin by hydroxyapatite chromatography as the method described by Cummins and Perry [23]. The proteins were eluted by a linear gradient of 1–200 mM phosphate buffer to separate the two subfractions: α (higher electrophoretic mobility) and β subunits (Fig.…”

Section: Methodsmentioning

confidence: 99%

Asymmetric myosin binding to the thin filament as revealed by a fluorescent nanocircuit

Castro-Zena

Root

2013

Archives of Biochemistry and Biophysics

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The interplay between myosin, actin, and striated muscle regulatory proteins involves complex cooperative interactions that propagate along the thin filament. A repeating unit of the tropomyosin dimer, troponin heterotrimer, and the actin protofilament heptamer is sometimes assumed to be able to bind myosin at any of its seven actins when activated even though the regulatory proteins are asymmetrically positioned along this repeating unit. Analysis of the impact of this asymmetry on actin and myosin interactions by sensitized emission luminescence resonance energy transfer spectroscopy and a unique fluorescent nanocircuit design reveals that the troponin affects the structure and function of myosin heads bound nearby in a different manner than myosin heads bound further away from the troponin. To test this hypothesis, a fluorescent nanocircuit reported the position of the myosin lever arm only when the myosin was bound adjacent to the troponin, or in controls, only when the myosin was bound distant from the troponin. Confirming the hypothesis, the myosin lever arm is predominantly in the prepowerstroke orientation when bound near troponin, but is predominantly in the postpowerstroke orientation when bound distant from troponin. These data are consistent with the hypothesis that troponin is responsible for the formation of myosin binding target zones along the thin filament.

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“…The relative amounts of α‐, β‐, and γ‐TMs that are expressed in a muscle cell are characteristic of the species and muscle fiber type and are also dependent on the stage of development and other factors such as hormone status [4,5]. The relative amounts of α‐TM are generally higher in fast fibers [6]. When α and β subunits are present, the αβ dimer is the preferred form [7].…”

Section: Introductionmentioning

confidence: 99%