High-pressure SANS and fluorescence unfolding study of calmodulin.
Biochim Biophys Acta
; 1844(9): 1560-8, 2014 Sep.
Article
en En
| MEDLINE
| ID: mdl-24862246
ABSTRACT
Apo-calmodulin, a small soluble mainly α protein, is a calcium-dependent protein activator. Calcium binding affects the calmodulin conformation but also its stability. Calcium free form unfolds between 40 and 80°C, whereas the calcium-saturated form is stable up to temperatures as high as 100°C, forbidding comparison of the thermal unfolding pathways of the two forms. Thus, this paper focuses especially on the conformation of pressure-induced unfolding states of both forms of calmodulin, by combining small-angle neutron scattering (SANS) with biophysical techniques such as tyrosines and ANS fluorescence. In contrast to heat denaturation (Gibrat et al., BBA, 2012), the pressure denaturation of calmodulin is reversible up to pressures of 3000bar (300MPa). A pressure-induced compact intermediate state has been found for the two calmodulin forms, but their unfolding pathways are different. A domain compaction and an increase of the ANS fluorescence of holo form have been evidenced. On the contrary, a domain dilatation and an ANS fluorescence decrease have been found for the apo form. The pressure induced an increase of the interdomain distance for both calmodulin forms, suggesting that the central linker of calmodulin is flexible in solution.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Apoproteínas
/
Calmodulina
/
Calcio
/
Desplegamiento Proteico
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
2014
Tipo del documento:
Article
País de afiliación:
Francia