The KnotProt 2.0 collects information about proteins with knots, slipknots, and knotoids. Such structures are defined in either probabilistic way, or deterministically based on disulfide or ion bonds. The knotting complexity of proteins is presented in the form of a matrix diagram that shows users the knot type of the entire polypeptide chain and of each of its subchains. The database presents extensive information about the biological function of entangled proteins and enables users to analyze their own structures.