Context-Dependent Heterotypic Assemblies of Inherently Disordered Peptides

Despite being ubiquitous within proteins and playing a crucial role in context-dependent interactions for protein functions, intrinsically disorder regions (IDRs), unlike structured motifs, are often overlooked for designing peptide assemblies. Here, we demonstrate using these regions for enabling context-dependent heterotypic assemblies of inherently disordered peptides (IDPs). We achieve this by attaching an aromatic segment to positively or negatively charged IDPs. While the same-charged peptides are unable to form assemblies on their own, mixing oppositely charged peptides creates nanofibers of heterotypic IDP assemblies. Cryo-EM analysis confirms the β-sheet arrangement within the ordered core of nanofibers, demonstrates conformational heterogeneity and a disorder-to-order continuum, and reveals unusual high volume density of hydrogen bonds between tyrosine and lysine e-amine. Additionally, this work demonstrates a post-assembly morphological change resulted from local conformational flexibility. While equal molar mixtures of the charged IDPs yield nanofibers, doubling the positively charged IDPs after assembly mainly produces bundles of nanofibers. Furthermore, reducing the number of aromatic amino acid residues reduces the bundle formation. Demonstrating context-dependent self-assembly of IDPs and revealing atomistic insights heterotypic assemblies of IDPs for the first time, this work illustrates a straightforward approach to enable heterotypic IDPs to self-assemble for the design of adaptive, multifunctional peptide nanomaterials.