Search for: All records

The designability of orthogonal coiled coil (CC) dimers, which draw on well‐established design rules, plays a pivotal role in fueling the development of CCs as synthetically versatile assembly‐directing motifs for the fabrication of bionanomaterials. Here, we aim to expand the synthetic CC toolkit through establishing a “minimalistic” set of orthogonal, de novo CC peptides that comprise 3.5 heptads in length and a single buried Asn to prescribe dimer formation. The designed sequences display excellent partner fidelity, confirmed via circular dichroism (CD) spectroscopy and Ni‐NTA binding assays, and are corroborated in silico using molecular dynamics (MD) simulation. Detailed analysis of the MD conformational data highlights the importance of interhelical E@g‐N@ainteractions in coordinating an extensive 6‐residue hydrogen bonding network that “locks” the interchain Asn‐Asn′ contact in place. The enhanced stability imparted to the Asn‐Asn′ bond elicits an increase in thermal stability of CCs up to ~15°C and accounts for significant differences in stability within the collection of similarly designed orthogonal CC pairs. The presented work underlines the utility of MD simulation as a tool for constructing de novo, orthogonal CCs, and presents an alternative handle for modulating the stability of orthogonal CCs via tuning the number of interhelical E@g‐N@acontacts. Expansion of CC design rules is a key ingredient for guiding the design and assembly of more complex, intricate CC‐based architectures for tackling a variety of challenges within the fields of nanomedicine and bionanotechnology. 

Abstract Intrinsically disordered proteins and protein regions (IDPs) are prevalent in all proteomes and are essential to cellular function. Unlike folded proteins, IDPs exist in an ensemble of dissimilar conformations. Despite this structural plasticity, intramolecular interactions create sequence-specific structural biases that determine an IDP ensemble’s three-dimensional shape. Such structural biases can be key to IDP function and are often measured in vitro, but whether those biases are preserved inside the cell is unclear. Here we show that structural biases in IDP ensembles found in vitro are recapitulated inside human-derived cells. We further reveal that structural biases can change in a sequence-dependent manner due to changes in the intracellular milieu, subcellular localization, and intramolecular interactions with tethered well-folded domains. We propose that the structural sensitivity of IDP ensembles can be leveraged for biological function, can be the underlying cause of IDP-driven pathology or can be used to design disorder-based biosensors and actuators. 

Abstract The successful integration of 2D nanomaterials into functional devices hinges on developing fabrication methods that afford hierarchical control across length scales of theentireassembly. We demonstrate structural control over a class of crystalline 2D nanosheets assembled from collagen triple helices. By lengthening the triple helix unit through sequential additions of Pro‐Hyp‐Gly triads, we achieved sub‐angstrom tuning over the 2D lattice. These subtle changes influence the overall nanosheet size, which can be adjusted across the mesoscale size regime. The internal structure was observed by cryo‐TEM with direct electron detection, which provides real‐space high‐resolution images, in which individual triple helices comprising the lattice can be clearly discerned. These results establish a general strategy for tuning the structural hierarchy of 2D nanomaterials that employ rigid, cylindrical structural units.