Design of metal-mediated protein assemblies via hydroxamic acid functionalities.

The self-assembly of proteins into sophisticated multicomponent assemblies is a hallmark of all living systems and has spawned extensive efforts in the construction of novel synthetic protein architectures with emergent functional properties. Protein assemblies in nature are formed via selective association of multiple protein surfaces through intricate noncovalent protein-protein interactions, a challenging task to accurately replicate in the de novo design of multiprotein systems. In this protocol, we describe the application of metal-coordinating hydroxamate (HA) motifs to direct the metal-mediated assembly of polyhedral protein architectures and 3D crystalline protein-metal-organic frameworks (protein-MOFs).

Enzyme-Directed Functionalization of Designed, Two-Dimensional Protein Lattices.

The design and construction of crystalline protein arrays to selectively assemble ordered nanoscale materials have potential applications in sensing, catalysis, and medicine. Whereas numerous designs have been implemented for the bottom-up construction of protein assemblies, the generation of artificial functional materials has been relatively unexplored. Enzyme-directed post-translational modifications are responsible for the functional diversity of the proteome and, thus, could be harnessed to selectively modify artificial protein assemblies.

An Exceptionally Stable Metal-Organic Framework Constructed from Chelate-Based Metal-Organic Polyhedra.

We report the rational design and synthesis of a water-stable metal-organic framework (MOF), Fe-HAF-1, constructed from supramolecular, Fe-hydroxamate-based polyhedra with mononuclear metal nodes. Owing to its chelate-based construction, Fe-HAF-1 displays exceptional chemical stability in organic and aqueous solvents over a wide pH range (pH 1-14), including in the presence of 5 M NaOH. Despite the charge neutrality of the Fe-tris(hydroxamate) centers, Fe-HAF-1 crystals are negatively charged above pH 4.

Constructing protein polyhedra via orthogonal chemical interactions.

Many proteins exist naturally as symmetrical homooligomers or homopolymers. The emergent structural and functional properties of such protein assemblies have inspired extensive efforts in biomolecular design. As synthesized by ribosomes, proteins are inherently asymmetric.

Self-Assembly of a Designed Nucleoprotein Architecture through Multimodal Interactions.

The co-self-assembly of proteins and nucleic acids (NAs) produces complex biomolecular machines (e.g., ribosomes and telomerases) that represent some of the most daunting targets for biomolecular design.

Author Correction: Hyperexpandable, self-healing macromolecular crystals with integrated polymer networks.

Change history: In this Letter, Alexander Groisman should have been listed as an author. This error has been corrected online.

Hyperexpandable, self-healing macromolecular crystals with integrated polymer networks.

The formation of condensed matter typically involves a trade-off between structural order and flexibility. As the extent and directionality of interactions between atomic or molecular components increase, materials generally become more ordered but less compliant, and vice versa. Nevertheless, high levels of structural order and flexibility are not necessarily mutually exclusive; there are many biological (such as microtubules, flagella , viruses) and synthetic assemblies (for example, dynamic molecular crystals and frameworks) that can undergo considerable structural transformations without losing their crystalline order and that have remarkable mechanical properties that are useful in diverse applications, such as selective sorption , separation , sensing and mechanoactuation .

Tunable Helicity, Stability and DNA-Binding Properties of Short Peptides with Hybrid Metal Coordination Motifs.

Given the prevalent role of α-helical motifs on protein surfaces in mediating protein-protein and protein-DNA interactions, there have been significant efforts to develop strategies to induce α-helicity in short, unstructured peptides to interrogate such interactions. Toward this goal, we have recently introduced hybrid metal coordination motifs (HCMs). HCMs combine a natural metal-binding amino acid side chain with a synthetic chelating group that are appropriately positioned in a peptide sequence to stabilize an α-helical conformation upon metal coordination.