Subcategory: STEM Research
Tandabany Dinadayalane - Department of Chemistry, Clark Atlanta University, Atlanta, GA
Co-Author(s): Jovian Lazare and Dalia Daggag, Department of Chemistry, Clark Atlanta University
Density functional theory (DFT) calculations at the M06-2X/6-31G(d) level were performed to investigate the interactions between two aromatic amino acids (AAAs) tyrosine (Tyr) and phenylalanine (Phe) with graphene. Two different sizes of graphene sheets with hydrogen termination at edges, small graphene (GS) with 62 carbon atoms and large graphene sheet (GL) with 186 carbon atoms were considered. Conformational analysis was done for tyrosine and phenylalanine using MMFF force field implemented in Spartan ’16. Two lowest energy conformers and one highest energy conformer for tyrosine and phenylalanine were chosen to examine the binding with graphene sheets. In our study, we considered 3-4 orientations for each of the three different conformers of Tyr and Phe to study interactions with GS and GL. Calculations were performed in the gas and aqueous phases. Binding energies with and without basis set superposition error (BSSE) were calculated. Our aim in this study is to answer the following questions: (i) Which conformer of the AAA provides the most stable complex? (ii) What is the preferred orientation of the AAA with graphene (pi-pi vs. C-H/N-H…pi)? (iii) How does the size of graphene sheet affect the binding strength? (iv) How does the binding affinity vary from gas phase to aqueous media by moving from Tyr to Phe? This study reveals that Tyr and Phe prefer to orient parallel (pi-pi interactions). Our detailed computational investigation of the binding of AAAs with graphene will provide knowledge required for graphene-based biological/biocompatible applications.
Funder Acknowledgement(s): TD acknowledges the National Science Foundation (NSF) for the financial support through HBCU-UP Research Initiation Award (Grant number 1601071)
Faculty Advisor: None Listed,