Modulating the Nucleated self-assembly of Tri-beta3-peptides using cucurbit[n]urils

The modulation of the hierarchical nucleated self-assembly of tri-β3-peptides has been studied. β3-Tyrosine provided a handle to control the assembly process through host-guest interactions with CB[7] and CB[8]. By varying the cavity size from CB[7] to CB[8] distinct phases of assembling tri-β3-peptides were arrested. Given the limited size of the CB[7] cavity, only one aromatic β3-tyrosine can be simultaneously hosted and, hence, CB[7] was primarily acting as an inhibitor of self-assembly. In strong contrast, the larger CB[8] can form a ternary complex with two aromatic amino acids and hence CB[8] was acting primarily as cross-linker of multiple fibers and promoting the formation of larger aggregates. General insights on modulating supramolecular assembly can lead to new ways to introduce functionality in supramolecular polymers

The self-assembly and dynamics of weakly multivalent, peptide-based, host-guest systems

Multivalency is the key principle dictating receptor-ligand interactions in biological systems. To understand these interactions in detail a model system taken out of biological complexity is required. Most of the model systems reported so far have been focused on employing strong intrinsic interactions between ligands and receptors. But strong intrinsic interactions in a multivalent system cause large changes in affinity with valency (i.e., cause a high multivalent enhancement factor) and cause the interaction pairs to be in the bound state for most of the time. These properties can lead to a kinetically trapped state of the multivalent complex, which is in contrast to biological systems in which lower multivalency enhancement factors avoid such a kinetically trapped state.\ud \ud To resolve this issue a weakly multivalent system has been developed in this thesis. The result is a model system with a small multivalency enhancement factor, thus ensuring higher valences not result in a kinetically trapped state of the complex.\ud \ud We envision that the weakly multivalent model system described in this thesis will help to understand the mechanism of multivalent interactions, for example, the interaction of the influenca virus with a cell, in a biological context. This improved understanding will help to design the next generation of molecular and regenerative medicines