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Binding of Levosimendan, a Calcium Sensitizer, to Cardiac Troponin C

Sorsa, Tia; Heikkinen, Sami; Abbott, M. Bret; Abusamhadneh, Ekram; Laakso, Tero; Tilgmann, Carola LU ; Serimaa, Ritva; Annila, Arto; Rosevear, Paul R. and Drakenberg, Torbjörn LU , et al. (2001) In Journal of Biological Chemistry 276(12). p.9337-9343
Abstract

Levosimendan is an inodilatory drug that mediates its cardiac effect by the calcium sensitization of contractile proteins. The target protein of levosimendan is cardiac troponin C (cTnC). In the current work, we have studied the interaction of levosimendan with Ca2+-saturated cTnC by heteronuclear NMR and small angle x-ray scattering. A specific interaction between levosimendan and the Ca2+-loaded regulatory domain of recombinant cTnCC35S was observed. The changes in the NMR spectra of the N-domain of full-length cTnCC35S, due to the binding of levosimendan to the primary site, were indicative of a slow conformational exchange. In contrast, no binding of levosimendan to the regulatory domain... (More)

Levosimendan is an inodilatory drug that mediates its cardiac effect by the calcium sensitization of contractile proteins. The target protein of levosimendan is cardiac troponin C (cTnC). In the current work, we have studied the interaction of levosimendan with Ca2+-saturated cTnC by heteronuclear NMR and small angle x-ray scattering. A specific interaction between levosimendan and the Ca2+-loaded regulatory domain of recombinant cTnCC35S was observed. The changes in the NMR spectra of the N-domain of full-length cTnCC35S, due to the binding of levosimendan to the primary site, were indicative of a slow conformational exchange. In contrast, no binding of levosimendan to the regulatory domain of cTnCA-Cys, where all the cysteine residues are mutated to serine, was detected. Moreover, it was shown that levosimendan was in fast exchange on the NMR time scale with a secondary binding site in the C-domain of both cTnCC35S and cTnCA-Cys. The small angle x-ray scattering experiments confirm the binding of levosimendan to Ca2+-saturated cTnC but show no domain-domain closure. The experiments were run in the absence of the reducing agent dithiothreitol and the preservative sodium azide (NaN 3), since we found that levosimendan reacts with these chemicals, commonly used for preparation of NMR protein samples.

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publication status
published
subject
keywords
Calcium/metabolism*, Magnetic Resonance Spectroscopy, Troponin C/metabolism*, simendan, Myocardium/metabolism*
in
Journal of Biological Chemistry
volume
276
issue
12
pages
7 pages
publisher
American Society for Biochemistry and Molecular Biology
external identifiers
  • Scopus:0035937855
ISSN
0021-9258
DOI
10.1074/jbc.M007484200
language
English
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yes
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5367d08c-4b4a-4f67-9933-7cdb74636b07
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2016-04-11 13:06:14
date last changed
2016-11-20 04:32:23
@misc{5367d08c-4b4a-4f67-9933-7cdb74636b07,
  abstract     = {<p>Levosimendan is an inodilatory drug that mediates its cardiac effect by the calcium sensitization of contractile proteins. The target protein of levosimendan is cardiac troponin C (cTnC). In the current work, we have studied the interaction of levosimendan with Ca<sup>2+</sup>-saturated cTnC by heteronuclear NMR and small angle x-ray scattering. A specific interaction between levosimendan and the Ca<sup>2+</sup>-loaded regulatory domain of recombinant cTnC<sub>C35S</sub> was observed. The changes in the NMR spectra of the N-domain of full-length cTnC<sub>C35S</sub>, due to the binding of levosimendan to the primary site, were indicative of a slow conformational exchange. In contrast, no binding of levosimendan to the regulatory domain of cTnC<sub>A-Cys</sub>, where all the cysteine residues are mutated to serine, was detected. Moreover, it was shown that levosimendan was in fast exchange on the NMR time scale with a secondary binding site in the C-domain of both cTnC<sub>C35S</sub> and cTnC<sub>A-Cys</sub>. The small angle x-ray scattering experiments confirm the binding of levosimendan to Ca<sup>2+</sup>-saturated cTnC but show no domain-domain closure. The experiments were run in the absence of the reducing agent dithiothreitol and the preservative sodium azide (NaN <sub>3</sub>), since we found that levosimendan reacts with these chemicals, commonly used for preparation of NMR protein samples.</p>},
  author       = {Sorsa, Tia and Heikkinen, Sami and Abbott, M. Bret and Abusamhadneh, Ekram and Laakso, Tero and Tilgmann, Carola and Serimaa, Ritva and Annila, Arto and Rosevear, Paul R. and Drakenberg, Torbjörn and Pollesello, Piero and Kilpeläinen, Ilkka},
  issn         = {0021-9258},
  keyword      = {Calcium/metabolism*,Magnetic Resonance Spectroscopy,Troponin C/metabolism*,simendan,Myocardium/metabolism*},
  language     = {eng},
  month        = {03},
  number       = {12},
  pages        = {9337--9343},
  publisher    = {ARRAY(0xb96fa80)},
  series       = {Journal of Biological Chemistry},
  title        = {Binding of Levosimendan, a Calcium Sensitizer, to Cardiac Troponin C},
  url          = {http://dx.doi.org/10.1074/jbc.M007484200},
  volume       = {276},
  year         = {2001},
}