Tropomyosin: Evidence for no stagger between chains

Stewart, Murray

doi:10.1016/0014-5793(75)80668-5

Cited by 121 publications

(49 citation statements)

References 9 publications

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“…The sequence of the principal component of rabbit tropomyosin has recently been determined (Stone et al 1975). Direct experimental evidence (Johnson and Smillie 1975;Lehrer 1975;Stewart 1975) as well as stereochemical arguments (McLachlan and Stewart 1975) favour a molecule in which the chains are in register. On the basis of its X-ray diffraction pattern, tropomyosin is generally regarded as a two-stranded coiled-coil structure (for review see Fraser and MacRae 1973).…”

Section: Discussionmentioning

confidence: 99%

The Conformational Stabilities of Tropomyosins

Woods¹

1976

Aust. Jnl. Of Bio. Sci.

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The stability to denaturation by heat and guanidine hydrochloride of seven vertebrate (including skeletal, cardiac and smooth muscle) tropomyosins and three invertebrate tropomyosins was examined. The transition profiles were discontinuous and in many cases distinct plateaux were observed which indicated the presence of unique partially unfolded states at intermediate temperatures and guanidine hydrochloride concentrations.The denaturation by guanidine hydrochloride could be described in the majority of cases by a model in which the native state unfolds to a partially unfolded stable intermediate which then unfolds to the completely denatured state. On this basis it was possible to estimate the free energies of unfolding in water. It was shown that part of the IX-helical structure of tropomyosin is only marginally stable and the free energy of unfolding in water of this segment is less than values found for globular proteins, whereas another segment (or segments) has a stability comparable to that found for globular proteins. The stepwise unfolding may be explained in terms of the coiled-coil interactions in tropomyosin.Differences in stability were found between tropomyosins from different muscles of the same species as well as between species; no two tropomyosins giving the same denaturation profiles. The invertebrate tropomyosins showed a wider range of stabilities, that from scallop striated muscle being far more easily denatured than all the others. No correlation was found between the stability of tropomyosin and the type of regulatory system of the muscle. A comparison of the results from vertebrate and invertebrate species suggests that there has been no selection for proteins of higher or lower stability during the evolutionary time scale.

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Section: Discussionmentioning

confidence: 99%

The Conformational Stabilities of Tropomyosins

Woods¹

1976

Aust. Jnl. Of Bio. Sci.

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“…Fully North-Holland Publishing Company -Amsterdam reduced tropomyosin was obtained by exposure of the protein, at 2 mg/ml to 100 mM dithiothreitol for 48 h at 0°C. Tropomyosin was oxidized by bubbling air through the protein solution, at 3 mg/ml, in 20 mM HEPES buffer (pH 8.0) and 1 X lo-' M CuCls, i.e., following essentially the method of Stewart [7].…”

Section: Preparatiori Of Proteinsmentioning

confidence: 99%

Digestion of tropomyosin with trypsin

Gorecka

Drabikowski

1977

FEBS Letters

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“…We have used the techniques of Stewart [9], Johnson and Smillie [lo] , and Lehrer [ 111 to form disulfide bonds between the opposing sulfhydryls on each chain of tropomyosin in order to define the subunit pairing in skeletal-and smooth-muscle tropomyosins. The results indicate that adult skeletal-muscle …”

Section: Introductionmentioning

confidence: 99%