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6906867 
Journal Article 
The mutual relationship between H-bonding and pi-stacking interactions: the estimation of individual binding energies in the phenylalanine:G center dot center dot center dot C ternary complex 
Ebrahimi, A; Khorassani, SMH; Abedini, S; , 
2011 
1 
Molecular Physics
ISSN: 0026-8976
EISSN: 1362-3028 
TAYLOR & FRANCIS LTD 
ABINGDON 
2049-2055 
WOS:000295460800008 
The mutual relationship between stacked interaction and the individual hydrogen bonds in the phenylalanine: guanine center dot center dot center dot cytosine (Ph:G-C) and phenylalanine:cytosine center dot center dot center dot 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 pi-stacking and H-bonding results in the weakening of both interactions. The effect of pi-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 pi-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 pi-stacking energies decrease in the ternary complexes.