Vibrational Spectroscopy of Polymers

Hsu, Shaw Ling

doi:10.1002/0471440264.pst381.pub2

Cited by 2 publications

(1 citation statement)

References 278 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compared to the frequency of the amide I vibration, the Fermi resonance provides a more sensitive probe for the small conformational change of a molecule induced by interactions with the environment. − Here, Fermi resonance arises from intramolecular coupling between a fundamental vibration and an overtone or combination band of another vibration in the same part of the molecule when they have a close frequency and the same symmetry . In general, a minute change in the relevant vibrational energy level can cause a significant change in the Fermi resonance.…”

Section: Introductionmentioning

confidence: 99%

Fermi Resonance of the N-D Stretching Mode Probing the Local Hydrogen-Bonding Environment in Proteins

Pei,

Zhang,

Tan

et al. 2024

J. Phys. Chem. B

View full text Add to dashboard Cite

Local H-bonding interactions are crucial for proteins to undergo various structural transitions and form different secondary structures. However, identifying slight distinctions in the local H-bonding of proteins is rather challenging. Here, we demonstrate that the Fermi resonance of the N-D stretching mode can provide an effective probe for the localized Hbonding environment of proteins both at the surface/interface and in the bulk. Using sum frequency generation vibrational spectroscopy and infrared spectroscopy, we established a correlation between the Fermi resonance of the N-D mode and protein secondary structures. The H-bond of N-D•••C�O splits the N-D modes into two peaks (∼2410 and ∼2470 cm −1 ). The relative strength ratio (R) between the ∼2410 cm −1 peak and the ∼2470 cm −1 peak is very sensitive to H-bond strength and protein secondary structure. R is less than 1 for α-helical peptides, while R is greater than 1 for β-sheet peptides. For R < 2.5, both α-helical/loop structures and β-sheet structures exhibit almost identical Fermi coupling strengths (W = 28 cm −1 ). For R > 2.5, W decreases from 28 to 14 cm −1 and depends on the aggregation degree of the βsheet oligomers or fibrils. The initial local H-bonding status impacts the misfolding dynamics of proteins at the lipid bilayer interface.

show abstract