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Updated: Jul 16, 2025

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Structural and vibrational analysis of glycyl-L-phenylalanine and phase transition under high-pressure
José Avelar S Silva1, Daniel L Militão Vasconcelos2, Raphaela Araújo de Lima1
1Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, 60021-970, Fortaleza, CE, Brazil.
Abstract:
The structural and vibrational properties of the glycyl-L-phenylalanine dipeptide were investigated using vibrational spectroscopy (Raman and infrared) and first-principle calculations. Raman spectroscopy measurements were performed between 100 and 3200 cm-1 and infrared spectroscopy from 100 and 3200 cm-1 under ambient conditions. The conformational analysis of the zwitterionic form of the dipeptide was performed using the B3LYP functional, the 6-311++ base set and the Polarizable Continuum Model of solvation, determining the lowest energy conformation and assigning the vibrational modes. The effect of pressure on the glycyl-1-phenylalanine crystal was investigated using the Raman spectroscopy between 0.0 and -7.1 GPa in the spectral region of 100 - 3200 cm-1. As a result, conformational changes around 1.0 GPa were observed in the lattice modes and in some internal modes, showing a reorganization of the molecule in the crystal. In the decompression process, it was observed that the conformational change is reversible and the original Raman spectrum is recoverd.
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