Designed Two- and Three-Dimensional Protein Nanocage Networks Driven by Hydrophobic Interactions Contributed by Amyloidogenic Motifs

Abstract

Precise manipulation of protein self-assembly by noncovalent interactions into programmed networks to mimic naturally occurring nanoarchitectures in living organisms is a challenge due to its structural heterogeneity, flexibility, and complexity. Herein, by taking advantage of both the hydrophobic forces contributed by the "GLMVG" motif, a kind of amyloidogenic motif (AM), and the high symmetry of protein nanocages, we have built an effective protein self-assembly strategy for the construction of twodimensional (2D) or three-dimensional (3D) protein nanocage arrays. According to this strategy, "GLMVG" AMs from β-amyloid 42 were grafted onto the outer surface of a 24-mer ferritin nanocage close to its C 4 symmetry channels, initially resulting in the production of subgrade 2D nanocage arrays and ultimately generating 3D highly ordered arrays with a simple cubic packing pattern as the reaction time increases. More importantly, the reversibility and the formation rate of these protein arrays can be modulated by pH. This work provides a de novo design strategy for accurate control over 2D or 3D protein selfassemblies.

Structural Insight into Binary Protein Metal–Organic Frameworks with Ferritin Nanocages as Linkers and Nickel Clusters as Nodes

“…To prove this idea, we made a ferritin mutant named bisH‐SF where Thr157 was replaced with His 2 . BisH‐SF was purified according to our recently reported procedure . Native PAGE of this new protein exhibited a single band (Figure S2a, SI), indicating that it was purified to homogeneity.…”

“…So far, ferritin has been explored as a nanoplatform for the preparation of different nanomaterials or a vehicle for tumor imaging and drug delivery . Our recent research interests mainly focus on 2D and 3D self‐assembly of ferritin nanocages; amyloidogenic motif and aromatic stacking interactions were utilized to construct human ferritin assembly, and the interaction mechanism was speculated because of the lack of structural information . In this work, we chose recombinant shrimp ferritin (rSF) as building blocks to fabricate protein MOFs because it is a homopolymer, and more stable compared with mammal ferritins, and we were able to solve the crystal structure to clarify the molecular mechanism of this assembly.…”

“…To prove this idea, we made af erritin mutant namedb isH-SF where Thr157 was replaced with His 2 .B isH-SF was purified according to our recently reported procedure. [30,31] Native PAGE of this new protein exhibiteda single band ( Figure S2a, SI), indicating that it was purified to homogeneity.A se xpected, this protein is comprised of one type of subunit (FigureS2b, SI). Transmission electron microscopy (TEM) image revealed that the exteriord iameter of bisH-SF is % 12 nm ( Figure S2c), indicating that the above mutation has no effect on ferritin's shell-like structure.…”

“…[21] Our recent research interests mainly focuso n2 Da nd 3D self-assembly of ferritin nanocages;a myloidogenic motif and aromatic stacking interactions were utilized to construct human ferritin assembly,a nd the interaction mechanism was speculated because of the lack of structural information. [30,31] In this work, we chose recombinant shrimp ferritin (rSF) as buildingb locks to fabricate protein MOFs because it is ahomopolymer,and more stable compared with mammalf erritins,a nd we were able to solve the crystal structuret oc larify the molecular mechanism of this assembly. Our designs trategy for protein MOFs is based on ac ombination of the directionality of the symmetry rotation axes of a target protein and the strength of metal-coordination bonds.…”

Protein interface redesign facilitates conversion of zero-dimensional protein nanomaterials to their one- and two-dimensional analogues

“…It is well-known that protein-protein interactions (PPIs) at protein interfaces are the chief contributors to construct the diversi ed protein nanostructures [11][12][13] . Following Nature's inspiration to assemble protein building blocks into exquisite nanostructures, various self-assembly strategies, such as symmetry-directed design [14][15][16][17] , metal-coordination 7,18,19 , host-guest interactions 20,21 and the use of bifunctional ligands 22,23 have been applied mainly to construct one-, two-and threedimensional hierarchical protein nanostructures. In contrast to the above 1D, 2D and 3D protein architectures, Nature has also evolved a series of protein nanocages to ful ll a wide range of functions such as CO 2 xation by carboxysomes 24 , iron metabolism by ferritin 25 , DNA protection by Dps 26 , and nucleic acid storage and transport by viral capsids 27 .…”