Honors Theses

Date of Award

Spring 5-1-2020

Document Type

Undergraduate Thesis


Chemistry and Biochemistry

First Advisor

Nathan Hammer

Second Advisor

Ryan Fortenberry

Third Advisor

Greg Tschumper

Relational Format



Trimethylamine N-Oxide (TMAO), guanidinium, and urea are three important

osmolytes with their main significance to the biophysical field being in how they

uniquely interact with proteins. TMAO is known to stabilize and counteract the

destabilizing effects of both urea and guanidinium. The exact mechanisms by which

TMAO stabilizes and both guanidinium and urea destabilize folded proteins continue

to be debated in the literature. Some studies suggest that solvent interactions do not

play a large role in TMAO’s stabilizing effects and therefore advocate direct

stabilization, whereas others suggest that TMAO counteracts denaturation primarily

through an indirect effect of strong solvent interactions. Herein, we use Raman

spectroscopy to elucidate the physical interactions between the osmolytes of interest

in aqueous solutions to better understand how they interact with each other and affect

adjacent hydrogen-bonding networks of water. Comparing experiment to theory yields

good agreement, and it was determined that adding TMAO into both an aqueous

solution of guanidinium and an aqueous solution of urea induces a blue shift (shift to

higher energy) in both urea and guanidinium’s H-N-H bending modes, which is

indicative of direct interactions between the osmolytes.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.



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