Design, Synthesis, and Structural Characterization of π-Stacking Porous Peptide Materials

The level of complexity in natural systems like proteins allows for remarkable functions such as precise molecular recognition, catalysis, and signaling. Such functionality is permitted by structural plasticity, in which precisely tailored active sites can be achieved through reversible tweaking of amino acids throughout a protein’s hierarchical structure. Importantly, such natural systems are predominantly held together using noncovalent interactions, enabling high dynamic character. Achieving this level of function and plasticity in synthetic materials has been a fundamental challenge in research as protein synthesis and mimicry is difficult. Thus, solid-state porous materials have been heavily investigated due to their widespread uses. Zeolites, metal-organic frameworks, covalent-organic frameworks, and hydrogen-bonded organic frameworks have led to great achievements in biomimicry. However, their rigidity and lack of straight-forward structural tunability limits dynamic abilities and in turn, functionality. Constructing porous materials from peptidic scaffolds on the other hand, has helped improve these issues though there is much less literature exploring this area. Herein, this thesis provides a simple approach of creating crystalline porous, peptide material by leveraging noncovalent assemblies of helical peptide-peptide interactions as well as π-stacking. This new class of material, named UIC-1, highly tolerates mutations to functionalize its pores without disruption of the framework topology. The ability to create new topologies from UIC-1 is attainable through mutations of residues that perturb the peptide-peptide interactions, providing a simple route of pore diversification. Lastly, a comprehensive examination of dynamic mechanisms seen in UIC-1 and variants is illuminated via noncovalent binding of simple aromatic molecules. 7 unique conformational states, which have not been demonstrated in other synthetic systems, are elucidated using sets of discrete, dynamic mechanisms. These results show that the de novo class of porous peptide materials based on UIC-1 have implications with advanced biomimicry in the crystalline state beyond the scope of traditional porous materials.