COMPARISON OF INTRAMOLECULAR FORCES IN DIPEPTIDES WITH TWO AROMATIC RINGS: DOES DISPERSION DOMINATE?

Thomas, Jessica A.

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https://hdl.handle.net/2142/79428 Copy

Description

Title

COMPARISON OF INTRAMOLECULAR FORCES IN DIPEPTIDES WITH TWO AROMATIC RINGS: DOES DISPERSION DOMINATE?

Author(s)

Thomas, Jessica A.

Issue Date

22-Jun-15

Keyword(s)

Structure determination

Abstract

IR/UV double resonance spectroscopy has shown that the structure of the capped dipeptide Ac-Trp-Tyr-NH$_{2}$ is dominated by a hydrophobic interaction between the aromatic rings on the side chains. Using the same method, a similar molecule, Ac-Phe-Phe-NH$_{2}$, had three experimentally observed conformers including one similar to that of Ac-Trp-Tyr-NH$_{2}$. In this work, calculations were performed on additional dipeptides containing two aromatic rings to determine if the dispersion-dominated structure was among the lowest energy structures in all such cases. The B3LYP-DCP method developed by DiLabio and Torres was used to calculate the conformations of each dipeptide. Appending dispersion correction potentials (DCP) to B3LYP input files improves results for systems containing dispersion interactions without significantly increasing the calculation time. This method was used first on Ac-Trp-Tyr-NH$_{2}$ and Ac-Phe-Phe-NH$_{2}$ to confirm that it successfully identified the experimentally observed structures among the lowest energy results and was then applied to other capped dipeptides containing two aromatic rings including Ac-Phe-Tyr-NH$_{2}$ and Ac-Tyr-Phe-NH$_{2}$.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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http://hdl.handle.net/2142/79428

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