Email this article The Effect of Stabilizing Mutations in the Central Part of α-Chain of Tropomyosin on the Bending Stiffness of Reconstructed Thin Filaments that Contain Its αβ-Heterodimers
- Authors: Nabiev S.R.1, Nikitina L.V.1, Hertsen O.P.1, Matyushenko A.M.2, Shchepkin D.V.1, Kopylova G.V.1, Bershitsky S.Y.1, Tsaturyan A.K.3, Levitsky D.I.2,4
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Affiliations:
- Institute of Immunology and Physiology, Ural Branch
- Bach Institute of Biochemistry, Research Center of Biotechnology
- Institute of Mechanics
- Belozersky Institute of Physicochemical Biology
- Issue: Vol 63, No 1 (2018)
- Pages: 20-24
- Section: Molecular Biophysics
- URL: https://ogarev-online.ru/0006-3509/article/view/152491
- DOI: https://doi.org/10.1134/S0006350918010116
- ID: 152491
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Abstract
We studied the effect of the replacement of two highly conserved noncanonical residues in the α-chain of tropomyosin, that is, Asp137 and Gly126, with the canonical residues, Leu and Arg, on the mechanical properties of reconstructed thin filaments that contain αβ-heterodimers of tropomyosin. For this purpose, the reconstructed thin filaments that contain fibrillar actin, tropomyosin, and troponin were stretched with an optical trap. The resulting strain–force diagrams were analyzed using a mathematical model proposed previously in order to estimate the bending stiffness. It was shown that the thin filaments that contain αβ-heterodimers of tropomyosin with α-chains of the pseudo-wild type, i.e., that contain the C190A substitution, have approximately the same bending stiffness as the filament with αα-homodimers of tropomyosin. The stabilizing substitution D137L in the α-chain of tropomyosin did not cause a statistically significant change in the bending stiffness of the filaments that contain αβ-heterodimers of tropomyosin, whereas the G126R and G126R/D137L substitutions led to a moderate increase in this stiffness. This increase in stiffness was, however, much less pronounced than that for the filaments that contain αα-homodimers of tropomyosin with these substitutions in both α-chains. The relationship between the results obtained in this study and the previously published data on the effects of these stabilizing substitutions in the α-chain of tropomyosin on the structural and functional properties of thin filaments with αβ-heterodimers of tropomyosin is discussed.
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About the authors
S. R. Nabiev
Institute of Immunology and Physiology, Ural Branch
Email: Levitsky@inbi.ras.ru
Russian Federation, Yekaterinburg, 620049
L. V. Nikitina
Institute of Immunology and Physiology, Ural Branch
Email: Levitsky@inbi.ras.ru
Russian Federation, Yekaterinburg, 620049
O. P. Hertsen
Institute of Immunology and Physiology, Ural Branch
Email: Levitsky@inbi.ras.ru
Russian Federation, Yekaterinburg, 620049
A. M. Matyushenko
Bach Institute of Biochemistry, Research Center of Biotechnology
Email: Levitsky@inbi.ras.ru
Russian Federation, Moscow, 119071
D. V. Shchepkin
Institute of Immunology and Physiology, Ural Branch
Email: Levitsky@inbi.ras.ru
Russian Federation, Yekaterinburg, 620049
G. V. Kopylova
Institute of Immunology and Physiology, Ural Branch
Email: Levitsky@inbi.ras.ru
Russian Federation, Yekaterinburg, 620049
S. Y. Bershitsky
Institute of Immunology and Physiology, Ural Branch
Email: Levitsky@inbi.ras.ru
Russian Federation, Yekaterinburg, 620049
A. K. Tsaturyan
Institute of Mechanics
Email: Levitsky@inbi.ras.ru
Russian Federation, Moscow, 119991
D. I. Levitsky
Bach Institute of Biochemistry, Research Center of Biotechnology; Belozersky Institute of Physicochemical Biology
Author for correspondence.
Email: Levitsky@inbi.ras.ru
Russian Federation, Moscow, 119071; Moscow, 119992
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