Understanding and controlling the metal-directed assembly of terpyridine-functionalized coiled-coil peptides.

Metal-binding peptides are versatile building blocks in supramolecular chemistry. We recently reported a class of crystalline materials formed through a combination of coiled-coil peptide self-association and metal coordination. Here, we probe the serendipitously discovered metal binding motif that drives the assembly and apply these insights to exert rational control over structure and morphology in the materials.

Supramolecular Metal-Coordination Polymers, Nets, and Frameworks from Synthetic Coiled-Coil Peptides.

Metal coordination and peptide-directed self-assembly are two proven methods for creating defined supramolecular architectures. Here, we report a new class of crystalline materials based on coiled-coil peptides bearing unnatural metal-chelating terpyridine moieties. High-resolution structural characterization of lattices formed in the presence of Cu reveals a general assembly mechanism.

Comparison of design strategies for α-helix backbone modification in a protein tertiary fold.

We report here the comparison of five classes of unnatural amino acid building blocks for their ability to be accommodated into an α-helix in a protein tertiary fold context. High-resolution structural characterization and analysis of folding thermodynamics yield new insights into the relationship between backbone composition and folding energetics in α-helix mimetics and suggest refined design rules for engineering the backbones of natural sequences.

Origins of structural flexibility in protein-based supramolecular polymers revealed by DEER spectroscopy.

Modular assembly of bio-inspired supramolecular polymers is a powerful technique to develop new soft nanomaterials, and protein folding is a versatile basis for preparing such materials. Previous work demonstrated a significant difference in the physical properties of closely related supramolecular polymers composed of building blocks in which identical coiled-coil-forming peptides are cross-linked by one of two subtly different organic linkers (one flexible and the other rigid). Herein, we investigate the molecular basis for this observation by isolating a single subunit of the supramolecular polymer chain and probing its structure and conformational flexibility by double electron-electron resonance (DEER) spectroscopy.