Conformations of the regulatory domain of cardiac troponin C examined by residual dipolar couplings

Kimmo Pääkkönen, Tia Sorsa, Torbjörn Drakenberg, Piero Pollesello, Carola Tilgmann, Perttu Permi, Sami Heikkinen, Ilkka Kilpeläinen, Arto Annila (Corresponding Author)

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Abstract

Conformations of the regulatory domain of cardiac troponin C (cNTnC) were studied by means of residual dipolar couplings measured from samples dissolved in dilute liquid crystals. Changes in the main chain HN residual dipolar couplings revealed a conformational change in cNTnC due to the complexation with the second binding region (amino acids 148–163) of cardiac troponin I (cTnI). Formation of the complex is accompanied with a molecular realignment in the liquid crystal. The residual dipolar couplings measured for apo‐cNTnC and the complex with TnI were in agreement with the values computed from the corresponding closed and open solution structures, whereas for the calcium‐loaded conformation the correlation and quality factor were only modest. Ca2+‐cNTnC may be subject to conformational exchange. The data support the model that cardiac troponin C functions as a calcium‐dependent open–closed switch, such as the skeletal troponin C.

Original languageEnglish
Pages (from-to)6665-6672
JournalEuropean Journal of Biochemistry
Volume267
Issue number22
DOIs
Publication statusPublished - 2000
MoE publication typeA1 Journal article-refereed

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    Pääkkönen, K., Sorsa, T., Drakenberg, T., Pollesello, P., Tilgmann, C., Permi, P., Heikkinen, S., Kilpeläinen, I., & Annila, A. (2000). Conformations of the regulatory domain of cardiac troponin C examined by residual dipolar couplings. European Journal of Biochemistry, 267(22), 6665-6672. https://doi.org/10.1046/j.1432-1327.2000.01763.x