title: Multiple conformations of the proline-rich protein/epigallocatechin gallate complex determined by time-averaged nuclear Overhauser effects.
abstract: The structure of the complex between the heptapeptide Gln-Gly-Arg-Pro-Pro-Gln-Gly and the polyphenol (-)-epigallocatechin gallate (EGCG) has been determined using time-averaged nuclear Overhauser effects. Effective parameters for the force constant and time constant have been derived, allowing rapid and efficient calculation of structures that satisfy the input restraints. By using multiple start conformations, it is shown that conformational space is covered adequately and that the complex exists in one major conformation, in which the A ring of the EGCG is positioned over Pro5 and the D ring is over Pro4, with the B ring frequently close to the arginine side chain. Alternative conformations are also found, in which the prolines are almost always both involved in stacking interactions, with a strong preference for Pro4 to be involved. The structures are consistent with previous models for the interaction and suggest how precipitation of the complex could occur, which leads to the oral phenomenon of astringency. The method has promise as a general way of docking ligands onto receptors.
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Charlton
authors.forename: Edwin
authors.initials: E
authors.lastname: Haslam
authors.forename: Michael P
authors.initials: MP
authors.lastname: Williamson
mesh_terms: D000595:Amino Acid Sequence; D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D009842:Oligopeptides / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D009842:Oligopeptides; D002392:Catechin; D011392:Proline; C045651:epigallocatechin gallate