Calcium and peptide binding to folded and unfolded conformations of cardiac Troponin C. Electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry
UNSPECIFIED. (2002) Calcium and peptide binding to folded and unfolded conformations of cardiac Troponin C. Electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY, 8 (6). pp. 471-481. ISSN 1469-0667Full text not available from this repository.
Official URL: http://dx.doi.org/10.1255/ejms.523
The binding of Ca2+ and of a peptide (N-TnI) to human cardiac troponin C (TnC) and its isolated N- and C-terminal domains has been characterized by electrospray ionization Fourier transform ion cyclotron resonance (ESI FT-ICR) mass spectrometry. The peptide N-TnI corresponds to residues 1-29 of the cardiac-specific N-terminal extension of human cardiac troponin I (TnI). The binding of Ca2+ to intact TnC in the absence of the peptide was found to take a bimodal form with preferred stoichiometries of 1 : 1 TnC : Ca2+ and 1 : 3 TnC : Ca2+. It is concluded that TnC existed in two conformational isomers that had different binding affinities for Ca2+: the binding of 3 Ca2+ was characteristic of a folded conformation (TnC(A)) and the binding of 1 Ca2+ was characteristic of a partially unfolded conformation (TnC(B)). Both of these conformations contributed to the 8+ (and other) charge states of TnC, and were distinguished on the basis of their different Ca2+-binding affinities and not on the basis of the charge state. In the presence of the peptide, a complex with 1 : 1 : 1 TnC : peptide : Ca2+ stoichiometry was formed.
|Item Type:||Journal Article|
|Subjects:||Q Science > QC Physics|
|Journal or Publication Title:||EUROPEAN JOURNAL OF MASS SPECTROMETRY|
|Number of Pages:||11|
|Page Range:||pp. 471-481|
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