UV Resonance Raman and DFT Studies of Arginine Side Chains in Peptides: Insights into Arginine Hydration
Overview
Authors
Affiliations
We examined the UV resonance Raman (UVRR) spectra of four models of the Arg side chain, guanidinium (Gdn), ethylguanidinium (EG), arginine (Arg), and Ac-Arg-OMe (AAO) in H2O and D2O, in order to identify spectral markers that report on the environment of the Arg side chain. To elucidate the resonance Raman enhancement mechanism of the Arg side chain, we used density functional theory (DFT) to calculate the equilibrium geometries of the electronic ground state and the first excited state. We determined the vibrational mode frequencies of the ground state and the first derivative of the first electronic excited state potential energy with respect to each vibrational normal mode of the electronic ground state at the electronic ground state equilibrium geometry. The DFT calculations and the potential energy distributions reveal that, in addition to the Gdn group C-N stretching vibrations, the C-N bond stretching vibration of the Gdn group-methylene linkage is also strongly resonance-enhanced in EG, Arg, and AAO. From the UVRR spectra, we find that the Raman cross section and frequency of the ~1170 cm(-1) vibration of the Arg side chain depends on its hydration state and can be used to determine the hydration state of the Arg side chain in peptides and proteins. We examined the hydration of the Arg side chain in two polyAla peptides and found that in the α-helical conformation the Arg side chain in the AEP peptide (sequence: A9RA3EA4RA2) is less hydrated than that in the AP peptide (sequence: A8RA4RA4RA2).
Lighting the Path: Raman Spectroscopy's Journey Through the Microbial Maze.
Salbreiter M, Frempong S, Even S, Wagenhaus A, Girnus S, Rosch P Molecules. 2025; 29(24).
PMID: 39770046 PMC: 11870064. DOI: 10.3390/molecules29245956.
Mustafa R, Fitian M, Hamilton N, Li J, Silva W, Punihaole D J Phys Chem B. 2022; 126(42):8404-8414.
PMID: 36222425 PMC: 10413332. DOI: 10.1021/acs.jpcb.2c04939.
Ultraviolet Resonance Raman Spectroscopic Markers for Protein Structure and Dynamics.
Jakubek R, Handen J, White S, Asher S, Lednev I Trends Analyt Chem. 2020; 103:223-229.
PMID: 32029956 PMC: 7003616. DOI: 10.1016/j.trac.2017.12.002.
Self-Assembled Nanoscaled Metalloporphyrin for Optical Detection of Dimethylmethylphosphonate.
Wu M, Yang H, Wei H, Hu X, Qu B, Chen M Biomed Res Int. 2019; 2019:7689183.
PMID: 31011578 PMC: 6442447. DOI: 10.1155/2019/7689183.
New Insights into Quinine-DNA Binding Using Raman Spectroscopy and Molecular Dynamics Simulations.
Punihaole D, Workman R, Upadhyay S, Van Bruggen C, Schmitz A, Reineke T J Phys Chem B. 2018; 122(43):9840-9851.
PMID: 30336027 PMC: 6425490. DOI: 10.1021/acs.jpcb.8b05795.