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Updated: Aug 18, 2026

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Pressure-tuning FT-IR spectroscopic study on the helix-coil transition of Ala-rich oligopeptide in aqueous solution
Takahiro Takekiyo1, Akio Shimizu, Minoru Kato
1Department of Applied Chemistry, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Abstract:
We investigated the effect of pressure on the helix-coil transition of an Ala-rich peptide (AK16: YGAAKAAAAKAAAAKA-NH(2)) in aqueous solution by FT-IR spectroscopy. The spectra of the amide I' region of AK16 in aqueous solution was decomposed into some component bands using a curve fitting method. The peak at around 1635 cm(-1) corresponding to the solvent exposed alpha-helix conformer increases with increasing pressures, while the peak at around 1655 cm(-1) corresponding to the random coil conformer decreases. From the pressure dependence of the band intensities, we determined the volume change from the alpha-helix to random coil conformers of AK16 to be +10.5+/-0.3 cm(3)/mol. The positive volume change is different from the negative volume change generally observed in the pressure denaturation of proteins.
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