Human Insulin Hexamer

The structure shown here has been obtain from PDB as entry 1trz, which includes a hexameric form of human insulin. Imported into Chimera and modified to be represented in ribbon form (modified thickness of coils and ribbons, arrows and ect.) A Solid version can be found on Sketchfab as well. Insulin is synthesized in the pancreas by specialized (beta) cells. Initially synthesized as preproinsulin, the first 24 residues function as a signal peptide, direct the protein to the rough endoplasmic reticulum (rER) and are cleaved. The remaining protein, called proinsulin, is folded in the ER lumen and three disulfide linkages are formed. The mature insulin molecule retains two short peptides, N-terminal 30 residues (referred to as chain B) and C-terminal 21 residues (referred to as chain A). The 3 disulfide-linkages, described earlier, hold the two chains of insulin together. Mature insulin is stored in secretory vesicles within beta cells, ready to be released.