This content is part of a pedagogical resource focusing on teaching crystallographic symmetry, with related, comprehensive information available on the Bilbao Crystallographic Server. How the ? A deeper look into rhombohedral/hexagonal crystal packing ?
The video dv5020sup5.mp4 shows the "action of symmetry operations on the asymmetric unit," specifically how the atoms move, rotate, or translate. Key Concepts Illustrated in the Video H21(1).mp4
Zn ions, for example, are located directly on the rotation axis. This content is part of a pedagogical resource
The insulin dimer acts as the asymmetric unit within a crystal structure. It is a "giant" unit because it consists of hundreds of atoms. The video dv5020sup5
Insulin acts as a hormone that regulates blood glucose levels. The video highlights how this massive structure exists as a stable, inactive hexamer in the pancreas before dissociation into biologically active monomers.
These spheroids pack in a hexagonal system (rhombohedral shape) to form a crystal. The packing creates a "threefold symmetry axis" (Zn ions).