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True Origin of Amide I Shifts Observed in Protein Spectra Obtained with Sum Frequency Generation Spectroscopy.
- Source :
-
The journal of physical chemistry letters [J Phys Chem Lett] 2023 Jun 01; Vol. 14 (21), pp. 4949-4954. Date of Electronic Publication: 2023 May 22. - Publication Year :
- 2023
-
Abstract
- Accurate determination of protein structure at interfaces is critical for understanding protein interactions, which is directly relevant to a molecular-level understanding of interfacial proteins in biology and medicine. Vibrational sum frequency generation (VSFG) spectroscopy is often used for probing the protein amide I mode, which reports protein structures at interfaces. Observed peak shifts are attributed to conformational changes and often form the foundation of hypotheses explaining protein working mechanisms. Here, we investigate structurally diverse proteins using conventional and heterodyne-detected VSFG (HD-VSFG) spectroscopy as a function of solution pH. We reveal that blue-shifts of the amide I peak observed in conventional VSFG spectra upon lowering the pH are governed by the drastic change of the nonresonant contribution. Our results highlight that connecting changes in conventional VSFG spectra to conformational changes of interfacial proteins can be arbitrary, and that HD-VSFG measurements are required to draw unambiguous conclusions about structural changes in biomolecules.
- Subjects :
- Proteins chemistry
Spectrum Analysis
Vibration
Amides
Water chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1948-7185
- Volume :
- 14
- Issue :
- 21
- Database :
- MEDLINE
- Journal :
- The journal of physical chemistry letters
- Publication Type :
- Academic Journal
- Accession number :
- 37213084
- Full Text :
- https://doi.org/10.1021/acs.jpclett.3c00391