Complete set of H-bonded homoassociates of 9-methylguanine with participation of mutagenic tautomers: quantum-mechanical study

1Glushenkov, AN
1Hovorun, DM
1Institute of High Technology, Taras Shevchenko National University of Kyiv; Institute of Molecular Biology and Genetics of the NAS of Ukraine, Kyiv
Dopov. Nac. akad. nauk Ukr. 2016, 3:98-106
Section: Biophysics
Language: Ukrainian

For the first time on the MP2/6-311++G(2df,pd)//B3LYP/6-311++G(d,p) theory level, the complete family of m9Gua·m9Gua homoassociates in vacuum, which consists of 57 structures the interval 0–17.69 kcal/mol of relative Gibbs free energies under standard conditions, is obtained. Homoassociates are stabilized through classical (NH...N, NH...O, OH...N, OH...O) and weak (CH...N, CH...O) H-bonds, and van-der-Waals contacts. The structures of 11 m9Gua·m9Gua homoassociates are planar (3 of them are centrosymmetric), 7 structures are U-shaped, 12 structures have L-shaped noncanonical geometry, 2 structures have T-shaped geometry, 20 structures — spiral, 3 — cross shaped, 2 — significantly non-planar. It is proved that the methyl group of m9Gua in position 9 is a donor of H-bonding and influences the energy distribution of homoassociates. It is demonstrated that, during the self-association of m9Gua, its amino-group can be simultaneously a donor and an acceptor of an H-bond. A linear relation between the energy of CH...O/N H-bonds and their electron density in corresponding critical bonds is established.

Keywords: 9-methylguanine, complete family, complete set, guanine, H-bond, self-assembly, tautomeric hypothesis
  1. Kunkel T. A. J. Biol. Chem., 2004, 279:16895–16898.
  2. Rothemund P. W. K. Nature, 2006, 440: 297–302.
  3. Geary C., Rothemund P. W. K., Andersen E. S. Science, 2014, 345: 799–803.
  4. Liu L., Xia D., Klausen L. H., Dong M. Int. J. Mol. Sci., 2014, 15: 1901–1914.
  5. Leontis N. B., Wethof E. RNA, 2001, 7: 499–512.
  6. Lee J. C., Gutell R. R. J. Mol. Biol., 2004, 344: 1225–1249.
  7. Glushenkov A. N., Hovorun D. M. Dopov. Nac. akad. nauk Ukr., 2014, 9: 151–156.
  8. Glushenkov A. N., Hovorun D. M. Dopov. Nac. akad. nauk Ukr., 2014, 8: 133–137.
  9. Weinhold F., Landis C. R. Discovering Chemistry With Natural Bond Orbitals, New York: John Wiley & Sons Inc, 2012.
  10. Brandhorst K., Grunenberg J. J. Chem. Phys., 2010, 132: 184101.
  11. Iogansen A. V. Spectrochim. Acta. Part A., 1999, 55: 1585–1612.
  12. Espinosa E., Mollins E., Lecomte C. Chem. Phys. Lett., 1998, 285: 170–173.
  13. Brovarets' O. O., Hovorun D. M. Mol. Phys., 2014, 112: 3033–3046.
  14. Brovarets' O. O., Hovorun D. M. Phys. Chem. Chem. Phys., 2014, 16: 15886–15899.
  15. Brovarets' O. O., Yurenko Y. P., Hovorun D. M. J. Biolmol. Struct. Dyn., 2014, 32: 993–1022.