Amide Spectral Fingerprints are Hydrogen Bonding-Mediated

The origin of the peculiar amide spectral features of proteins in aqueous solution is investigated by exploiting a combined theoretical and experimental approach to study UV Resonance Raman (RR) spectra of simple dipeptide molecular models.

UVRR spectra are recorded by tuning Synchrotron Radiation at several excitation wavelengths and modeled by using a recently developed multiscale protocol based on a polarizable QM/MM approach. Thanks to the unparalleled agreement between theory and experiment, we demonstrate that specific hydrogen bond interactions, which dominate hydration dynamics around these solutes, play a crucial role in the selective enhancement of amide signals. These results further argue the capability of vibrational spectroscopy methods as valuable tools for refined structural analysis of peptides and proteins in aqueous solution.
We have shown that the QM/QMw/FQ promisingly going beyond standard methodologies based on more crude approximations and is, therefore, expected to open up new possibilities for novel applications in a truly synergistic partnership with advanced experimental techniques applied to biologically relevant samples, as well as shed new light regarding the details of physicochemical phenomena that characterize the functioning of life.

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J. Phys. Chem. Lett. 13, 6200-6207  (2022) 
Ultima modifica il Martedì, 05 Luglio 2022 11:15