Electrostatic potential studies as a consequence of cation-π interaction in cytochrome c fold of alpha proteins

Abstract

Interactions between cationic and aromatic side chains of amino acid residues, the so-called cation-π interactions, are thought to contribute to the overall stability of the folded structure of peptides and proteins. We have analyzed the electrostatic behavior of residues involved in cation-π interactions for understanding the consequences of these non-covalent interactions. The average value of electrostatic potential for Arg and Lys were found to be positive which signifies their donor nature whereas Phe, Tyr and Trp showed negative values as they are acceptors. Similar trends were observed at the alpha carbon atom. We also observed that there is an opposite behavior of Lys as compared to Arg, Phe, Tyr and Trp towards electrostatic potential development on the last heavy atom. Furthermore the structural parameters like hydrophobicity and conservation score of interacting residues show that Lys to be acting totally different as compared to other residues and hence was found to be most influenced.