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Atomic dipole approximation and energies of interactions between purine and pyrimidine bases. I. Electrostatic interactions of adenine with uracil, thymine, thiouracils, dihydrouracil, and 5‐fluorouracil
Author(s) -
Geller M.,
Jaworski A.,
Pohorille A.
Publication year - 1979
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560150403
Subject(s) - thymine , uracil , chemistry , dipole , pyrimidine , computational chemistry , discrete dipole approximation , atomic physics , chemical physics , stereochemistry , physics , dna , organic chemistry , biochemistry
The atomic dipole approximation has been employed to calculate the energies of electrostatic interaction between adenine and various pyrimidine derivatives. Minima of the interaction energy for various planar configurations were determined. Inclusion of the “monopole–dipole” and “dipole–dipole” terms in the multipole expansion improves considerably the agreement with experimental data. The effect of sulfur substitution has been investigated in detail. Formation of NH…S hydrogen bonds is less favorable than of NH…O bonds, due largely to the lower atomic dipole of the sulfur atom resulting from the shift of the π‐electron charge toward the neighboring carbon. The results are relevant to the interactions of thiouracils in nucleic acids.