Molecular mechanisms of 33-mer gliadin peptide oligomerisation.
Phys Chem Chem Phys
; 21(40): 22539-22552, 2019 Oct 16.
Article
en En
| MEDLINE
| ID: mdl-31588935
The proteolytic resistant 33-mer gliadin peptide is an immunodominant fragment in gluten and responsible for the celiac disease and other gluten-related disorders. Meanwhile, the primary structure of the 33-mer is associated with the adaptive immune response in celiac patients, and the structural transformation of the 33-mer into protofilaments activates a primordial innate immune response in human macrophages. This means that accumulation, oligomerisation and structural transformation of the 33-mer could be the unknown first event that triggers the disease. Herein, we reveal the early stepwise mechanism of 33-mer oligomerisation by combining multiple computational simulations, tyrosine cross-linking, fluorescence spectroscopy and circular dichroism experiments. Our theoretical findings demonstrated that the partial charge distribution along the 33-mer molecule and the presence of glutamine that favours H-bonds between the oligomers are the driving forces that trigger oligomerisation. The high content of proline is critical for the formation of the flexible PPII secondary structure that led to a ß structure transition upon oligomerisation. Experimentally, we stabilised the 33-mer small oligomers by dityrosine cross-linking, detecting from dimers to higher molecular weight oligomers, which confirmed our simulations. The relevance of 33-mer oligomers as a trigger of the disease as well as its inhibition may be a novel therapeutic strategy for the treatment of gluten-related disorders.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Phys Chem Chem Phys
Asunto de la revista:
BIOFISICA
/
QUIMICA
Año:
2019
Tipo del documento:
Article
País de afiliación:
Argentina
Pais de publicación:
Reino Unido