Interaction of the second binding region of troponin I with the regulatory domain of skeletal muscle troponin C as determined by NMR spectroscopy.
J Biol Chem
; 272(45): 28494-500, 1997 Nov 07.
Article
en En
| MEDLINE
| ID: mdl-9353310
Two dimensional 1H,15N-heteronuclear single quantum correlation NMR was used to monitor the resonance frequency changes of the backbone amide groups belonging to the 15N-labeled regulatory domain of calcium saturated troponin C (N-TnC) upon addition of synthetic skeletal N-acetyl-troponin I 115-131-amide peptide (TnI115-131). Utilizing the change in amide chemical shifts, the dissociation constant for 1:1 binding of TnI115-131 to N-TnC in low salt and 100 mM KCl samples was determined to be 28 +/- 4 and 24 +/- 4 microM, respectively. The off rate of TnI115-131 was determined to be 300 s-1 from observed N-TnC backbone amide 1H,15N-heteronuclear single quantum correlation cross-peak line widths, which is on the order of the calcium off rates (Li, M. X., Gagné, S. M., Tsuda, S., Kay, C. M., Smillie, L. B., and Sykes, B. D. (1995) Biochemistry 34, 8330-8340), and agrees with kinetic expectations for biological regulation of muscle contraction. The TnI115-131 binding site on N-TnC was determined by mapping of chemical shift changes onto the N-TnC NMR structure and was demonstrated to be in the "hydrophobic pocket" (Gagné, S. M., Tsuda, S., Li, M. X., Smillie, L. B., and Sykes, B. D. (1995) Nat. Struct. Biol. 2, 784-789).
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Músculo Esquelético
/
Troponina C
/
Troponina I
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Biol Chem
Año:
1997
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Estados Unidos