An example of an eleven-chain beta cylinder formed by 1RRX green fluorescent protein
β-cylinder - a kind of tertiary structure of proteins; A β-folded layer folded to form a closed structure in which the first chain is connected by hydrogen bonds to the latter. As a rule, β-chains in β-cylinders are located in antiparallel orientation. Most often, β-cylinders form proteins such as porins and other membrane penetrating proteins, and proteins that bind hydrophobic ligands inside the cylinder, such as lipocalins .