Modeling the conformation of polyphenols and their complexation with polypeptides: self-association of catechin and its complexation with L-proline glycine oligomers.

Abstract

Over the past 10 years, several scientific thrusts have come together in the study of flavanoids that make it possible to move forward into the study of complexation between polyphenols and polypeptides. Enhanced understanding of the conformational properties of flavanoid monomers and polyflavanoids through molecular modeling, combined with the detailed NMR experimental data now in the literature, provide the foundation.1–13 Recent work using conformational searching techniques with the GMMX6–8 protocol has shown additional detail about the distribution of pseudo equatorial and pseudo low-energy axial conformers in the ensemble, as shown in figure 1. This leads to information about the relationship between the conformer ensemble and the Boltzmann averaged NMR proton coupling constants that one would expect to observe in a solution. Figure 1 also illustrates the pseudo equatorial to axial transformation that takes place in all catechin or (+)-catechin-(4α→8)-(+)-catechin (B3) dimer complexes during the conformer searches and which would also be expected to occur in solution. Interest continues to further understand the details about this conformer distribution as well as in the prediction of complexation of tannins with metal ions and proteins. Although the GMMX software has given many interesting results, it is limited in handling cases that require systematic conformational searching of molecules combined in a complex. In addition, there are no solvent model options.KeywordsLower Energy StructureAmber Force FieldPyran RingMMFF Force FieldAxial ConformerThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.