Titre :

Revisiting the phase transition sequence in L-methionine: Description of the disordering mechanism in an essential amino acid

Auteur(s) :

Guinet, Yannick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Paccou, Laurent [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Danede, Florence [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Hedoux, Alain [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207

Titre de la revue :

Journal of Chemical Physics

Nom court de la revue :

J. Chem. Phys.

Numéro :

156

Pagination :

034501

Éditeur :

AIP Publishing

Date de publication :

2022-01-18

ISSN :

0021-9606

Discipline(s) HAL :

Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Matière Condensée [cond-mat]/Matière Molle [cond-mat.soft]
Physique [physics]/Matière Condensée [cond-mat]/Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

Résumé en anglais : [en]

Raman spectroscopy investigations on L-methionine (L-Met) performed in large temperature range (170 K – 420 K) and in a wide spectral window (5 – 3600 cm-1) have revealed an extended disordering mechanism triggered by ...
Lire la suite >Raman spectroscopy investigations on L-methionine (L-Met) performed in large temperature range (170 K – 420 K) and in a wide spectral window (5 – 3600 cm-1) have revealed an extended disordering mechanism triggered by thermally activated motions of the terminal side-chain atoms, from 250 K up to 390 K. This very progressive disordering process is characterized by two thermodynamic features, the first corresponding to a broad endotherm (250 K → 310 K) marking the beginning of the process while the second, ending the disordering transformation is a sharp endothermic peak at 390 K. These thermodynamic events are correlated with the softening of lattice vibrations and the increase of the quasielastic scattering, considered as the signatures of displacive phase transitions. The amorphous like band-shape of the low-frequency Raman spectrum collected above 390 K, resulting from the strong anharmonicity of local motions, is contrasting with the detection of additional Bragg peaks above 390 K by X-ray diffraction, consistent with the Cp jump accompanying the endothermic peak. These observations suggest that L-Met is progressively dynamically disordered adopting additional configurations in the crystalline lattice, through rotations of CH3 and the side-chain flexibility not clearly detected by X-ray diffraction. These results should be crucial for considering the stability of dried proteins composed of methionine residues.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Établissement(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Matériaux Moléculaires et Thérapeutiques

Date de dépôt :

2022-01-28T09:04:27Z
2022-02-01T10:38:37Z