Topological Chirality of Proteins

摘要: A few rare instances are known in which conformational restriction on polypeptide folding patterns by disulfide cross-links results topological chirality. We now show that, once the role played covalently bound cofactors (prosthetic groups) conjugated proteins is taken into account, chirality fact more common than previously realized. Iron-sulfur examples of native Fe& clusters induce even absence cross-links. Quinoproteins with recognized to contain catenated substructures, and thus provide Fist example complexity a protein. The present study strongly suggests that may be wide Occurrence among diverse classes proteins. constitutional formulae (primary structures) given molecular graphs.' With exceptions, described below, these graphs reported planar.2 Hence, becausp nonplanarity necessary (though not sufficient) condition for chirality: it would appear though made up L-amino acids, higher- order chiralities imparted secondary structures convolutions polypeptidechains, thegreat majorityof chemically (and geometrically) chiral molecules topologtcally