The mutual relationship between H-bonding and π-stacking interactions: the estimation of individual binding energies in the phenylalanine:G ··· C ternary complex

• Published in: Molecular physics Vol. 109; no. 16; pp. 2049 - 2055
• Main Authors: Ebrahimi, A., Khorassani, S.M. Habibi, Abedini, S.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 20.08.2011
• Subjects: cytosine; Electron density; Energy use; guanine; Guanines; H-bonding; Hydrogen bonds; individual hydrogen bond; Mathematical analysis; Molecular physics; Phenylalanine; Rings (mathematics); π-stacking
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268976.2011.609144

The mutual relationship between stacked interaction and the individual hydrogen bonds in the phenylalanine:guanine ··· cytosine (Ph:G-C) and phenylalanine:cytosine ··· guanine (Ph:C-G) complexes have been studied at the MPWB1K/6-311++G** and M05-2X/cc-pVDZ levels of theory. The interplay of π-stacking and H-bonding results in the weakening of both interactions. The effect of π-stacking on the geometries and individual hydrogen bond (HB) energies of guanine-cytosine (G-C) base pair have been investigated using electron densities calculated by the atoms in molecules (AIM) method at the hydrogen bond critical points (BCP). The results of AIM analysis are in good agreement with the calculated individual hydrogen bond energies. The π-stacking interactions strengths the HB1 and weakens HB2 and HB3 in the Ph:G-C complexes, while the opposite is true in the Ph:C-G complex. With the increase in the distance between phenylalanine ring and the groups involved in H-bond interactions the change in the H-bond energy increases and the changes in the individual H-bond and π-stacking energies decrease in the ternary complexes.