High-pressure SANS and fluorescence unfolding study of calmodulin
| Autor: | Burkhard Annighöfer, Roland P. May, Marie-Claire Bellissent-Funel, Constantin T. Craescu, Yves Blouquit, Liliane Assairi, Gaston Hui Bon Hoa, Gabriel Gibrat |
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| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular Protein Denaturation Protein Folding Calmodulin Protein Conformation Biophysics chemistry.chemical_element Calcium Biochemistry Anilino Naphthalenesulfonates Analytical Chemistry Scattering Small Angle Pressure Intermediate state Humans Denaturation (biochemistry) Molecular Biology Fluorescent Dyes Protein Unfolding biology Chemistry Activator (genetics) Circular Dichroism Temperature Fluorescence Small-angle neutron scattering Recombinant Proteins Crystallography Neutron Diffraction Spectrometry Fluorescence biology.protein Thermodynamics Apoproteins Linker |
| Zdroj: | Biochimica et biophysica acta. 1844(9) |
| ISSN: | 0006-3002 |
| Popis: | 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 3000 bar (300 MPa). 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. |
| Databáze: | OpenAIRE |
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