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Updated: Jun 10, 2025

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Phase-transition of hydrophobic dipeptide l-phenylalanyl-l-alanine under high pressure via Raman spectroscopy
Adrya J P Cordeiro1, Kelly C Alves2, Elder A V Mota3
1Department of Physics, Federal University of Ceará, CEP: 60021-970 Fortaleza, CE, Brazil.
Abstract:
The study conducted on l-Phenylalanyl-l-Alanine (C12H16N2O3) dehydrated crystals under high-pressure conditions up to 7.0 GPa using Raman spectroscopy revealed significant modifications in both lattice and internal modes. Particularly, alterations were observed in modes associated with carbonyl and NH2 functionalities around 1600 cm-1. The Raman spectra exhibited distinct changes in modes related to torsions and stretching of the ring, suggesting a potential conformational change in specific pressure intervals: 2.6-3.0 GPa, and 5.0-5.1 GPa. Furthermore, notable changes between 0.4 and 1.0 GPa hinted at a structural transformation in the crystal. Additionally, Scanning Electron Microscopy-Field Emission Gun (SEM-FEG) was employed to elucidate the crystal pattern of Phe-Ala·2H2O. The ambient study, incorporating calculations, infrared, and Raman spectroscopy, contributed to a comprehensive understanding of vibrational mode assignments. This research sheds light on the behavior of l-Phenylalanyl-l-Alanine dehydrated crystals under varying pressure conditions, offering valuable insights for medicinal and pharmacological applications.
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