[2FT-1] Biophysics, Protein Folding (2P-45～2P-60)

[2P-52*] Solubility parameters of amino acids on liquid-liquid phase separation and aggregation of proteins

^○Akira Nomoto, Suguru Nishinami, Kentaro Shiraki (Pure and Appl. Sci., Univ. Tsukuba)

Interactions between amino acids and water determine the solution behaviors of proteins for folding, aggregation, and liquid-liquid phase separation (LLPS). Biophysical properties of respective amino acids, such as solubility, hydropathy, and conformational parameter, have well described the behavior of protein folding and aggregation both in vitro and in vivo. However, the propensity of LLPS is difficult to evaluate due to the multiple interactions among different amino acids. Here we investigate the solubility of amino acids (SA) in the solution of 20 kinds of amino acids to evaluate the interaction between two different amino acids in water molecules. The parameter of SA in amino acid solutions (PSAS) was varied depending on the kinds of amino acid solutions. The PSAS was mainly described by the amino acid side chain interactions that stabilize LLPS. Interestingly, the PSAS of aromatic amino acid in arginine and lysine solution did not coincident with the propensity of SA in water. The PSAS would be essential for a deeper understanding of LLPS and aggregation of proteins.