title: DPT tautomerisation of the wobble guanine·thymine DNA base mispair is not mutagenic: QM and QTAIM arguments.
abstract: We have shown for the first time, connecting QM methods with QTAIM analysis and using the methodology of the sweeps of the energetical, electron-topological and geometrical parameters, that the tautomerisation of the wobble guanine·thymine (wG·T) DNA base mispair into the wG(*)·T(*) base mispair induced by the double proton transfer (DPT), which undergoes a concerted asynchronous pathway, is not mutagenic. The wG·T → wG(*)·T(*) DPT tautomerisation does not result in the transition of the G base into its mutagenic tautomeric form G(*) able to mispair with the T base within the Watson-Crick base pairing scheme. This observation is explained by the so-called quantum protection of the wG·T DNA base mispair from its mutagenic tautomerisation - the dynamical non-stability of the tautomerised wG(*)·T(*) base mispair and significantly negative value of the Gibbs free energy of activation for the reverse reaction of the wG·T → wG(*)·T(*) DPT tautomerisation.
authors.affiliation: a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Akademika Zabolotnoho Str., 03680 Kyiv , Ukraine.
authors.forename: Ol'ha O
authors.initials: OO
authors.lastname: Brovarets'
authors.forename: Roman O
authors.initials: RO
authors.lastname: Zhurakivsky
authors.forename: Dmytro M
authors.initials: DM
authors.lastname: Hovorun
mesh_terms: D020137:Base Pair Mismatch; D020029:Base Pairing; D003198:Computer Simulation; D004247:DNA / Q000737:chemistry; D006147:Guanine / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011789:Quantum Theory; D013237:Stereoisomerism; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry*
chemical_list: D006147:Guanine; D004247:DNA; D013941:Thymine
keywords: B3LYP and MP2 levels of QM theory; QTAIM analysis; cooperativity of the H-bonds; mutagenic tautomer of the guanine; sweeps of the energetical,electron-topological, geometrical, polar and NBO parameters along the IRC; the double proton transfer; wobble guanine·thymine DNA base mispair