A highly controllable protein self-assembly system with morphological versatility induced by reengineered host-guest interactions.

Manipulating proteins to self-assemble into highly ordered nanostructures not only provides insights into the natural protein assembly process but also allows access to advanced biomaterials. Host-guest interactions have been widely used in the construction of artificial protein assemblies in recent years. CB[8] can selectively associate with two tripeptide Phe-Gly-Gly (FGG) tags with an extraordinarily high binding affinity (K = 1.

An ion signal responsive dynamic protein nano-spring constructed by high ordered host-guest recognition.

A protein self-assembly nano-spring was developed through host-guest interactions between cucurbit[8]uril and tripeptide FGG tags of fusion protein FGG-recoverin-GST. Fine control of the conformational changes of the Ca(2+)-responsive domain allows for a 50% stretch of the protein nano-spring as it switches from the contracted state to the extended state.

Reversible pH-controlled switching of an artificial antioxidant selenoenzyme based on pseudorotaxane formation and dissociation.

A pH-responsive artificial selenoenzyme was constructed by reversible binding between organoselenium compound a1 nd CB[6] to form a pseudorotaxane-based molecular switch in response to pH stimuli. The glutathione peroxidase (GPx) activity of the artificial selenoenzyme can be switched on/off in a mild and body suitable environment between pH = 7 and pH = 6.

Self-assembly of cricoid proteins induced by "soft nanoparticles": an approach to design multienzyme-cooperative antioxidative systems.

A strategy to construct high-ordered protein nanowires by electrostatic assembly of cricoid proteins and "soft nanoparticles" was developed. Poly(amido amine) (PAMAM) dendrimers on high generation that have been shown to be near-globular macromolecules with all of the amino groups distributing throughout the surface were ideal electropositive "soft nanoparticles" to induce electrostatic assembly of electronegative cricoid proteins. Atomic force microscopy and transmission electron microscopy all showed that one "soft nanoparticle" (generation 5 PAMAM, PD5) could electrostatically interact with two cricoid proteins (stable protein one, SP1) in an opposite orientation to form sandwich structure, further leading to self-assembled protein nanowires.

Quantum-dot-induced self-assembly of cricoid protein for light harvesting.

Stable protein one (SP1) has been demonstrated as an appealing building block to design highly ordered architectures, despite the hybrid assembly with other nano-objects still being a challenge. Herein, we developed a strategy to construct high-ordered protein nanostructures by electrostatic self-assembly of cricoid protein nanorings and globular quantum dots (QDs). Using multielectrostatic interactions between 12mer protein nanoring SP1 and oppositely charged CdTe QDs, highly ordered nanowires with sandwich structure were achieved by hybridized self-assembly.

Construction of a highly stable artificial glutathione peroxidase on a protein nanoring.

Stable Protein One (SP1) is a boiling-stable oligomeric protein. The unique characteristics of SP1 offer a scaffold to design artificial enzymes against extreme temperature. Here, an efficient antioxidase is successfully constructed on the ring-shaped SP1 homododecamer.