Title :

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

Author(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

Journal title :

Journal of Chemical Physics

Abbreviated title :

J. Chem. Phys.

Volume number :

156

Pages :

034501

Publisher :

AIP Publishing

Publication date :

2022-01-18

ISSN :

0021-9606

HAL domain(s) :

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]

English abstract : [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 ...
Show more >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.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Moléculaires et Thérapeutiques

Submission date :

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