(362g) Rational Design of Additives for Inhibition of Protein Aggregation

Protein aggregation is the most common degradation pathway for proteins. Aggregation leads to a decrease in efficacy of protein drugs and could elicit an immunological response. A common approach to solving the aggregation problem is to add low molecular weight cosolvents, such as sugars, salts, polyols etc. While ubiquitously used, this approach can be inefficient and does not always enable the discovery of stable protein solution formulations. Therefore, the rational design of cosolvents, which offers a significant improvement over commonly used cosolvents is highly desired. Arginine, a naturally occurring amino acid has been widely used to suppress protein aggregation, purify proteins using Protein-A affinity resins, and to improve the refolding efficiency of proteins. In this study, we show that arginine strongly self-associates in solution which leads to the enhanced crowding around macromolecule. Due to the crowding around the macromolecule, the free energy of the encounter complex formed when two proteins are associating increases. Furthermore, cosolvents are designed based on the molecular level understanding of Arginine mechanism. The designed cosolvents offer an order of magnitude improvement over commonly used cosolvents with regards to slowing protein aggregation.