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Further evidence for the cardiac troponin C mediated calcium sensitization by levosimendan : Structure-response and binding analysis with analogs of levosimendan

Levijoki, Jouko; Pollesello, Piero; Kaivola, Juha; Tilgmann, Carola LU ; Sorsa, Tia; Annila, Arto; Kilpeläinen, Ilkka and Haikala, Heimo (2000) In Journal of Molecular and Cellular Cardiology 32(3). p.479-491
Abstract

Levosimendan, an inodilatory drag discovered using troponin C as a target protein, has a cardiac effect deriving from the calcium sensitization of contractile proteins. The aim of this study was to give further evidence that levosimendan binds to cardiac troponin C and that the binding involves amino acid residues on helix ε of the N-terminal domain of this calcium-binding protein. Nine organic molecules, obtained by chemical modification of levosimendan, were tested both for their calcium-dependent binding to troponin C and troponin complex affinity Hplc columns, and for their ability to increase the calcium sensitivity of myofilaments in cardiac skinned fibers. A good correlation between the calcium sensitization and the... (More)

Levosimendan, an inodilatory drag discovered using troponin C as a target protein, has a cardiac effect deriving from the calcium sensitization of contractile proteins. The aim of this study was to give further evidence that levosimendan binds to cardiac troponin C and that the binding involves amino acid residues on helix ε of the N-terminal domain of this calcium-binding protein. Nine organic molecules, obtained by chemical modification of levosimendan, were tested both for their calcium-dependent binding to troponin C and troponin complex affinity Hplc columns, and for their ability to increase the calcium sensitivity of myofilaments in cardiac skinned fibers. A good correlation between the calcium sensitization and the calcium-dependent binding to troponin complex (r= 0.90) and to cardiac troponin C (r = 0.91) for the analogs of levosimendan was shown. In addition, the effect of levosimendan on the calcium-induced conformational changes in native and point-mutated cTnC was studied. Cys84→Ser, Asp87→Lys and Asp88 →Ala point-mutated cTnC were shown to maintain a high affinity to calcium, but their Ca2+ titration curves were not influenced by levosimendan as for the native protein. Finally, it was demonstrated that the NMR chemical shifts of the terminal methyl groups of Met47, Met81, and Met85 on calcium-saturated cTnC were changed after addition of levosimendan in water solution at pH 7.4. This effect was not seen when adding an analog of levosimendan, which did not bind to the troponin C affinity HPLC column and did not increase the calcium-induced tension in cardiac skinned fibers. (C) 2000 Academic Press.

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Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
keywords
Affinity Hplc, Calcium binding, Calcium sensitizer, Ctnc, Dansylated troponin, Nmr, Skinned fibers, Troponin complex
in
Journal of Molecular and Cellular Cardiology
volume
32
issue
3
pages
13 pages
publisher
Elsevier
external identifiers
  • Scopus:0033844678
ISSN
0022-2828
DOI
10.1006/jmcc.1999.1093
language
English
LU publication?
no
id
98577ee6-716c-4903-9709-209f8cfc0c0b
date added to LUP
2016-04-11 13:07:00
date last changed
2017-02-03 13:15:10
@article{98577ee6-716c-4903-9709-209f8cfc0c0b,
  abstract     = {<p>Levosimendan, an inodilatory drag discovered using troponin C as a target protein, has a cardiac effect deriving from the calcium sensitization of contractile proteins. The aim of this study was to give further evidence that levosimendan binds to cardiac troponin C and that the binding involves amino acid residues on helix ε of the N-terminal domain of this calcium-binding protein. Nine organic molecules, obtained by chemical modification of levosimendan, were tested both for their calcium-dependent binding to troponin C and troponin complex affinity Hplc columns, and for their ability to increase the calcium sensitivity of myofilaments in cardiac skinned fibers. A good correlation between the calcium sensitization and the calcium-dependent binding to troponin complex (r= 0.90) and to cardiac troponin C (r = 0.91) for the analogs of levosimendan was shown. In addition, the effect of levosimendan on the calcium-induced conformational changes in native and point-mutated cTnC was studied. Cys84→Ser, Asp87→Lys and Asp88 →Ala point-mutated cTnC were shown to maintain a high affinity to calcium, but their Ca<sup>2+</sup> titration curves were not influenced by levosimendan as for the native protein. Finally, it was demonstrated that the NMR chemical shifts of the terminal methyl groups of Met47, Met81, and Met85 on calcium-saturated cTnC were changed after addition of levosimendan in water solution at pH 7.4. This effect was not seen when adding an analog of levosimendan, which did not bind to the troponin C affinity HPLC column and did not increase the calcium-induced tension in cardiac skinned fibers. (C) 2000 Academic Press.</p>},
  author       = {Levijoki, Jouko and Pollesello, Piero and Kaivola, Juha and Tilgmann, Carola and Sorsa, Tia and Annila, Arto and Kilpeläinen, Ilkka and Haikala, Heimo},
  issn         = {0022-2828},
  keyword      = {Affinity Hplc,Calcium binding,Calcium sensitizer,Ctnc,Dansylated troponin,Nmr,Skinned fibers,Troponin complex},
  language     = {eng},
  number       = {3},
  pages        = {479--491},
  publisher    = {Elsevier},
  series       = {Journal of Molecular and Cellular Cardiology},
  title        = {Further evidence for the cardiac troponin C mediated calcium sensitization by levosimendan : Structure-response and binding analysis with analogs of levosimendan},
  url          = {http://dx.doi.org/10.1006/jmcc.1999.1093},
  volume       = {32},
  year         = {2000},
}