Quantifying hydropathy of self-assembling biomaterials*

Self-assembly is ubiquitous and, unsurprisingly, central to life. In biological systems, the interactions of protein, lipid, glycoproteins, and nucleic acids lead to the micro and macromolecular structures essential to life functions. All these interactions are related to the relative hydropathy of the interacting molecules. Several research articles on amino acid hydropathy have attempted to describe protein folding and assembly. However, self-assembly is more intricate than the chemical nature of the aggregating molecule. Our recent work showed that the molecule's three-dimensional structure is a critical determinant in self-assembly. We have developed a computational tool called PARCH (Protocol for Assigning a Residue's Character on a Hydropathy) Scale, which makes no assumptions about the chemical nature of the molecule to quantify its hydropathy. We have calculated parch values of residues in nucleic acids, biomimetics, and amino acid residues in more than 1,000 folded proteins. This work will feature several examples of macromolecular self-assembly that manifest from the chemical and topological heterogeneity of the molecule.