Atomic model and micelle dynamics of QS-21 saponin

QS-21 is a saponin extracted from Quillaja saponaria, widely investigated as a vaccine immunoadjuvant. However, QS-21 use is mainly limited by its chemical instability, significant variety in molecular composition and low tolerance dose in mammals. Also, this compound tends to form micelles in a con...

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Detalles Bibliográficos
Autores: Pedebos, Conrado, Pol-Fachin, Laércio, Pons Pons, Ramon, Teixeira, Cilâine Verônica, Teixeira, Hugo F.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2014
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/128751
Acceso en línea:http://hdl.handle.net/10261/128751
Access Level:acceso abierto
Palabra clave:Adjuvant
Micelle
Glycoconjugates
SAXS
Molecular dynamics
Saponins
QS-21
Descripción
Sumario:QS-21 is a saponin extracted from Quillaja saponaria, widely investigated as a vaccine immunoadjuvant. However, QS-21 use is mainly limited by its chemical instability, significant variety in molecular composition and low tolerance dose in mammals. Also, this compound tends to form micelles in a concentration-dependent manner. Here, we aimed to characterize its conformation and the process of micelle formation, both experimentally and computationally. Therefore, molecular dynamics (MD) simulations were performed in systems containing different numbers of QS-21 molecules in aqueous solution, in order to evaluate the spontaneous micelle formation. The applied methodology allowed the generation of micelles whose sizes were shown to be in high agreement with small-Angle X-ray scattering (SAXS). Furthermore, the ester linkage between fucose and acyl chain was less solvated in the micellar form, suggesting a reduction in hydrolysis. This is the first atomistic interpretation of previous experimental data, the first micellar characterization of saponin micelles by SAXS and first tridimensional model of a micelle constituted of saponins, contributing to the understanding of the molecular basis of these compounds.