Unfolding and folding pathway of lysozyme induced by sodium dodecyl sulfate.
Soft Matter
; 11(39): 7769-77, 2015 Oct 21.
Article
em En
| MEDLINE
| ID: mdl-26308474
Proteins may exhibit an unfolding or folding state in the presence of a surfactant. In the present study, the unfolding and folding pathway of hen egg white lysozyme (HEWL) induced by sodium dodecyl sulfate (SDS) is studied. The stoichiometry obtained from isothermal titration calorimetry (ITC) provides guidelines for other techniques. The fluorescence spectra and circular dichroism show that the fluorescence properties and secondary structure of proteins undergo a two-step change upon binding with SDS, in which the intensity decreases, the emission blue shifts and the helical conformation decreases at low ratios of SDS to HEWL, while all of them return to the native-like state upon the addition of SDS at higher ratios. At the end of the binding, HEWL presents a higher α-helical content but its tertiary structure is lost compared to its native state, which is namely a molten globule state. Small angle X-ray scattering (SAXS) analysis and the derived model reveal that the complexes possess a decorated core-shell structure, with the core composed of dodecyl chains and the shell consisting of SDS head groups with a protein in molten globule state. Five binding steps, including the individual details involved in the denaturation, were obtained to describe the unfolding and folding pathway of HEWL induced by SDS. The results of this study not only present details about the denaturation of protein induced by SDS and the structure of the complexes involved in each binding step, but also provide molecular insights into the mechanism of the higher helical conformation of proteins in the presence of surfactant micelles.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dodecilsulfato de Sódio
/
Muramidase
Limite:
Animals
Idioma:
En
Revista:
Soft Matter
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Reino Unido