Fig. 1 |.

Packing arrangement in ferritin crystals and their expansion-contraction mediated by the infused hydrogel network. a-c, The fcc packing arrangement of ferritin crystals (Protein Data Bank identifier, PDB ID, 6B8F). The unit cell, the 200 plane and the 111 plane are outlined in black, green and red, respectively. d, Ca-mediated intermolecular interactions between ferritin molecules in the lattice. Ca²+ ions (blue) are coordinated by two pairs of D84 and Q86 side-chains (magenta). e, Schematic representation of the formation, expansion and contraction of ferritin crystal-hydrogel hybrids.