Solution structure and main chain dynamics of the regulatory domain (Residues 1-91) of human cardiac troponin C.
J Biol Chem
; 273(25): 15633-8, 1998 Jun 19.
Article
en En
| MEDLINE
| ID: mdl-9624156
ABSTRACT
The three-dimensional structure of calcium-loaded regulatory, i.e. N-terminal, domain (1-91) of human cardiac troponin C (cNTnC) was determined by NMR in water/trifluoroethanol (919 v/v) solution. The single-calcium-loaded cardiac regulatory domain is in a "closed" conformation with comparatively little exposed hydrophobic surface. Difference distance matrices computed from the families of Ca2+-cNTnC, the apo and two-calcium forms of the skeletal TnC (sNTnC) structures reveal similar relative orientations for the N, A, and D helices. The B and C helices are closer to the NAD framework in Ca2+-cNTnC and in apo-sNTnC than in 2.Ca2+-sNTnC. However, there is an indication of a conformational exchange based on broad 15N resonances for several amino acids measured at several temperatures. A majority of the amides in the alpha-helices and in the calcium binding loop exhibit very fast motions with comparatively small amplitudes according to the Lipari-Szabo model. A few residues at the N and C termini are flexible. Data were recorded from nonlabeled and 15N-labeled samples, and backbone dynamics was investigated by 15N T1, T2, and heteronuclear nuclear Overhauser effect as well as by relaxation interference measurements.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Troponina C
/
Miocardio
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
1998
Tipo del documento:
Article
País de afiliación:
Finlandia