Molecular topology of multiple-disulfide polypeptide chains

• Published in: Journal of the American Chemical Society Vol. 111; no. 16; pp. 6132 - 6136
• Main Author: Mao, Boryeu
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.08.1989
• Subjects: Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; hypotheses; Physics; Dynamical topology; Theoretical study; Graph theory; Macromolecule; Polypeptide
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00198a022

Molecular topology of the polypeptide chain in a stable folded protein is characterized from analyzing the graph representation of molecular covalent structure and the embedding of such a graph. A subset of topologies (i.e., embedded graphs) that do not contain knotted structures is enumerated and classified for some graphs. As a working hypothesis, it is proposed that topologies of the finite polypeptide chain in a stable, folded globular protein can be represented by this subset. Thus, for any polypeptide chain containing three or fewer disulfides, there is only one topology for the polypeptide. Topological stereoisomerism, i.e., the existence of multiple possibilities for the molecular topology of nonplanar polypeptide chains, indicates that the correct prediction of molecular topology must be a criterion for any scheme that predicts tertiary structure of these proteins.