Chiral Sum Frequency Generation for In Situ Probing Proton Exchange in Antiparallel β-Sheets at Interfaces
Document Type
Article
Publication Date
2013
MeSH Terms
Spectrum Analysis, Deuterium Exchange Measurement
Subject: LCSH
Spectrum analysis, Deuterium, Hydrogen
Disciplines
Chemical Engineering | Chemistry
Abstract
Studying hydrogen/deuterium (H/D) exchange in proteins can provide valuable insight on protein structure and dynamics. Several techniques are available for probing H/D exchange in the bulk solution, including NMR, mass spectroscopy, and Fourier transform infrared spectroscopy. However, probing H/D exchange at interfaces is challenging because it requires surface-selective methods. Here, we introduce the combination of in situ chiral sum frequency generation (cSFG) spectroscopy and ab initio simulations of cSFG spectra as a powerful methodology to probe the dynamics of H/D exchange at interfaces. This method is applied to characterize H/D exchange in the antiparallel β-sheet peptide LK7β. We report here for the first time that the rate of D-to-H exchange is about 1 order of magnitude faster than H-to-D exchange in the antiparallel structure at the air/water interface, which is consistent with the existing knowledge that O–H/D dissociation in water is the rate-limiting step, and breaking the O–D bond is slower than breaking the O–H bond. The reported analysis also provides fundamental understanding of several vibrational modes and their couplings in peptide backbones that have been difficult to characterize by conventional methods, including Fermi resonances of various combinations of peptide vibrational modes such as amide I and amide II, C–N stretch, and N–H/N–D bending. These results demonstrate cSFG as a sensitive technique for probing the kinetics of H/D exchange in proteins at interfaces, with high signal-to-noise N–H/N–D stretch bands that are free of background from the water O–H/O–D stretch.
DOI
10.1021/ja3119527
Repository Citation
Fu, Li; Xiao, Dequan; Wang, Zhuguang; Batista, Victor; and Yan, Elsa C.Y., "Chiral Sum Frequency Generation for In Situ Probing Proton Exchange in Antiparallel β-Sheets at Interfaces" (2013). Chemistry and Chemical Engineering Faculty Publications. 12.
https://digitalcommons.newhaven.edu/chemicalengineering-facpubs/12
Publisher Citation
Fu, L., Xiao, D., Wang, Z., Batista, V. S., & Yan, E. C. Y. (2013). Chiral Sum Frequency Generation for In Situ Probing Proton Exchange in Antiparallel β-Sheets at Interfaces. Journal of the American Chemical Society, 135(9), 3592–3598. http://doi.org/10.1021/ja3119527
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