Biology cage self-assembly

The design of new proteins that can assemble into filaments, symmetric cages, and regular assays was described by Yeates and Padilla.These investigations are based on the consideration that proteins self-assemble to fulfill their biological functions and also as part of a... 

Synthetic control over the physical and chemical properties of a nanoparticle can be tuned according to its biological micro- or nano-environment. Some of the most notable platforms that are currently being used for the controlled synthesis of metal oxides include the apoprotein ferritin, viral capsids or bacterial cages however, recently adapted biotemplates, such as self-assemble peptide nanorings or porous butterfly wings, have been used as unique platforms and have yielded interesting structures. These molecular architectures offer constrained environments that yield a small distribution of nanoparticle size under ambient conditions, and will be discussed as viable alternatives for the synthesis of functional nanomaterials. 

The defined architecture of the metalloprotein ferritin, a natural complex of iron oxide, is found in almost all domains of life and has been used as a constrained reaction vessel for the synthesis of a number of non-natural metal oxides [28, 34]. The protein ferritin consists of 24 subunits that self-assemble into a cage, consisting of a threefold hydrophilic channel coordinated to a fourfold hydrophobic channel [20, 28]. In biology, Fe(ll) is introduced into the core of the apoprotein through its hydrophiUc charmels where the ferrous ion is catalytically oxidized to a less-soluble ferric ion, Fe(lll) [20]. The ferric ion then undergoes a series of hydrolytic polymerizations to form the insoluble ferric oxyhydroxide mineral (ferrihydrite), which is physically constrained by the size of the protein cage (12 nm outer diameter, 8nm inner diameter) [35]. The enzyme ferrous oxidase is coordinated within the protein cage, the interior and exterior of which is electrostatically dissimilar, to produce spatially defined minerals. 

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