(546d) Preservation of Protein Stability and Activity By Confinement in Michael-Type Addition Polyethylene Glycol Hydrogels
AIChE Annual Meeting
Wednesday, November 10, 2021 - 4:24pm to 4:42pm
We hypothesized that confinement would stabilize protein structure, and thus be correlated with higher ÎGunfolding values; interestingly, we found that the m-values instead correlated with confinement. We did not observe any significant difference in ÎGunfolding of proteins in free buffer, crowded (PEG-OH), and confined spaces (PEG-hydrogel). However, proteins confined in hydrogel had a lower m-value magnitude, suggesting that proteins were less unfolded in confinement. We suggest that the conformational stabilization arose from a change in the entropy of unfolding. The unfolded protein structure is less favorable in confined space vs free buffer solution due to excluded volume and spatial barriers limiting the number of possible unfolded conformations. Also, we observed that under mild stressed conditions such as incubation at 50°C, lysozyme activity was equal to or greater in confinement compared with free and crowded spaces.
Therefore, when comparing crowded vs confined environments, we found that the m-value is more affected when the protein is confined compared with the free protein in a buffer or crowded solution due to the physical characteristics of each environment. Ongoing studies are investigating additional proteins that are unstable and have therapeutic significance. Ultimately, a deeper understanding of protein conformational stability in these different microenvironments can provide for rationally-designed technologies for the improved formulation, storage and delivery of unstable protein therapeutics.