Rapid evaluation of the binding energies in hydrogen-bonded amide-thymine and amide-uracil dimers in gas phase.
The binding energies and the equilibrium hydrogen bond distances as well as the potential energy curves of 48 hydrogen-bonded amide-thymine and amide-uracil dimers are evaluated from the analytic potential energy function established in our lab recently. The calculation results show that the potential energy curves obtained from the analytic potential energy function are in good agreement with those obtained from MP2/6-311+G** calculations by including the BSSE correction. For all the 48 dimers, the analytic potential energy function yields the binding energies of the MP2/6-311+G** with BSSE correction within the error limits of 0.50 kcal/mol for 46 dimers, only two differences are larger than 0.50 kcal/mol and the largest one is only 0.60 kcal/mol. The analytic potential energy function produces the equilibrium hydrogen bond distances of the MP2/6-311+G** with BSSE correction within the error limits of 0.050 Å for all the 48 dimers. The analytic potential energy function is further applied to four more complicated hydrogen-bonded amide-base systems involving amino acid side chain and β-sheet. The values of the binding energies and equilibrium hydrogen bond distances obtained from the analytic potential energy function are also in good agreement with those obtained from MP2 calculations with the BSSE correction. These results demonstrate that the analytic potential energy function can be used to evaluate the binding energies in hydrogen-bonded amide-base dimers quickly and accurately.
School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian, People's Republic of China.
Yang
Y
Li
Xiao-Nan
XN
Jiang
Chang-Sheng
CS
Wang
D000577:Amides / Q000737:chemistry*; D019281:Dimerization; D005740:Gases / Q000737:chemistry*; D006860:Hydrogen Bonding; D011789:Quantum Theory; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry*; D014498:Uracil / Q000737:chemistry*
D000577:Amides; D005740:Gases; D014498:Uracil; D013941:Thymine