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Raman spectroscopic and quantum chemical investigation of the effects of trimethylamine N‐oxide on hydrated guanidinium and hydrogen‐bonded water networks
Author(s) -
Verville Genevieve A.,
Byrd Mary Hannah,
Kamischke Andrew,
Smith Shelly A.,
Magers David H.,
Hammer Nathan I.
Publication year - 2021
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.6061
Subject(s) - chemistry , trimethylamine n oxide , trimethylamine , guanidinium chloride , osmolyte , hydrogen bond , raman spectroscopy , aqueous solution , crystallography , inorganic chemistry , molecule , organic chemistry , biochemistry , physics , optics , enzyme
The effects of trimethylamine N‐oxide (TMAO) on guanidinium chloride and hydrogen‐bonded networks of water are explored in this joint Raman spectroscopic and quantum chemical study. Both TMAO and guanidinium are osmolytes that affect the stability of proteins, as TMAO is known to stabilize and counteract the destabilizing effects of guanidinium. While guanidinium is very similar in chemical structure to urea, the exact mechanisms of the molecular interactions between guanidinium, TMAO, and proteins continue to be investigated. Herein, we use Raman spectroscopy to elucidate the physical interactions between TMAO and guanidinium in aqueous solutions to better understand how these important osmolytes interact with each other and affect adjacent hydrogen‐bonding networks of water. Comparing experiment to theory yields good agreement and allows for the identification and tracking of different vibrational modes. It was determined that adding TMAO into an aqueous solution of guanidinium induces a blue shift (shift to higher energy) in guanidinium's H‐N‐H bending modes, which is indicative of direct interactions between the two osmolytes and similar to the earlier results observed for TMAO interacting with urea.