Abstract
A study of the competition between intra- and intermolecular hydrogen bonds and its influence on the stability of the Cys-Asn-Ser tripeptide in aqueous solution was performed by using the averaged solvent electrostatic potential from molecular dynamics method (ASEP/MD). The model combines a DFT-B3LYP/6-311+G(d) quantum treatment in the description of the solute molecule with NVT molecular dynamics simulations in the description of the solvent. In gas phase, the most stable structure adopts a C5 conformation. Somewhat higher in energy are found the PP(II) and C7eq structures. In solution, the stability order of the different conformers is reversed: the PP(II) structure becomes the most stable, and the C5 structure is strongly destabilized. The conformational equilibrium is shifted toward conformations in which the intramolecular hydrogen bonds (IHB) have been substituted with intermolecular hydrogen bonds with the water molecules. The solvent stabilizes extended structures without IHBs that are not stable in vacuum. The effect of the protonation state on the conformational equilibrium was also analyzed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
