<p> Appendix A. Supplementary material</p><p>Encapsulation of metal cations (Cu2+, Zn2+, Ca2+ and Ba2+) by the Phe-Phe di-peptide investigated using natural bond orbital theory and molecular dynamics simulation </p><p>S. Bhunia, A. Singh, and A. K. Ojha</p><p>______Contents Pages ______</p><p>Table S1 Computed relative energy values (kcal/mol) of Phe-Phe + 3 Cu2+/Zn2+ low energy conformers with the 6-31+G(d) basis set at B3LYP and MP2 level of theories.</p><p>Fig. S1 Molecular dynamics simulation’s trajectory for the binding motif 4 Phe-Phe + Cu2+/COO-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>Fig. S2 Molecular dynamics simulation’s trajectory for the binding motif 5 Phe-Phe + Cu2+/CO-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>Fig. S3 Molecular dynamics simulation’s trajectory for the binding motif 6 Phe-Phe + Zn2+/CO-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>Fig. S4 Molecular dynamics simulation’s trajectory for the binding motif 7 2+ Phe-Phe + Zn /COO-NH-NH2 using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>Fig. S5 Molecular dynamics simulation’s trajectory for the binding motif 8 Phe-Phe + Zn2+/COO-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>Fig. S6 Molecular dynamics simulation’s trajectory for the binding motif 9 Phe-Phe + Ca2+/CO-COOH-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>Fig. S7 Molecular dynamics simulation’s trajectory for the binding motif 10 Phe-Phe + Ca2+ /CO-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K. 1 Fig. S8 Molecular dynamics simulation’s trajectory for the binding motif 11 Phe-Phe + Ba2+/CO-COOH-Benzene using 90000 steps with an interval of 0.0001 ps at constant number of particles, pressure and temperature (NPT) at 300 K.</p><p>2 Table S1 Computed relative energy values (kcal/mol) of Phe-Phe + Cu2+/Zn2+ complexes employing the 6-31+G(d) basis set at B3LYP and MP2 level of theories.</p><p>Binding motifs B3LYP MP2 Phe-Phe + Cu2+ complex Phe-Phe + Cu2+/COO-Benzene 0.00 0.00 Phe-Phe + Cu2+/CO-Benzene 5.20 12.75 Phe-Phe + Cu2+/COOH-Benzene 9.08 16.13 2+ Phe-Phe + Cu / NH-NH2 27.86 31.14 Phe-Phe + Zn2+ complex Phe-Phe + Zn2+/CO-Benzene 0.00 0.00 2+ Phe-Phe + Zn /COO-NH-NH2 1.78 0.67 Phe-Phe + Zn2+/COO-Benzene 17.64 35.26 Phe-Phe + Zn2+/COOH-Benzene 32.54 63.54</p><p>3 Fig. S1</p><p>4 Fig. S2</p><p>5 Fig. S3</p><p>6 Fig. S4</p><p>7 Fig. S5</p><p>8 Fig. S6</p><p>9 Fig. S7</p><p>Fig. S8 10 11</p>