Theoretical searches and spectral computations of preferred conformations of various absolute configurations for a cyclodipeptide, cordycedipeptide A from the culture liquid of Cordyceps sinensis

• The conformational stability is influenced by the intramolecular hydrogen bonds.
• Only the preferred conformation of 3S screw configuration can display the negative optical rotation.
• The preferred conformation of 3S screw configuration has the positive lowest energy band of the electronic CD spectrum.

A cyclic dipeptide often has the multiple configurations and the abundant conformations. The density functional theory (DFT) method is used to search the preferred conformation of the most probable configuration for cordycedipeptide A isolated from the culture liquid of Cordyceps sinensis. The time-dependent DFT approach is exploited to describe the profile of electronic circular dichroism (CD). The calculated results show that the most probable configuration is 3S6R7S, whose preferred conformation has a negative optical rotation and a positive lowest energy electronic CD band.

On the basis of the DFT and time-dependent DFT computations, as the global minimum, the preferred conformation of 3S6R7S configuration for cordycedipeptide A has a negative optical rotation and a positive lowest energy band of electronic CD.Figure optionsDownload as PowerPoint slide