Investigation of the Ergopeptide Epimerization Process

Ergopeptides, like ergocornine and alpha-ergocryptine, exist in an S-and in an R-configuration. Kinetic experiments imply that certain configurations are preferred depending on the solvent. The experimental methods are explained in this article. Furthermore, computational methods are used to understand this configurational preference. Standard quantum chemical methods can predict the favored configurations by using minimum energy calculations on the potential energy landscape. However, the explicit role of the solvent is not revealed by this type of methods. In order to better understand its influence, classical mechanical molecular simulations are applied. It appears from our research that folding the ergopeptide molecules into an intermediate state (between the S-and the R-configuration) is mechanically hindered for the preferred configurations.