The Roothaan equations have been recently modified for computing molecular interactions between weakly bonded systems at the SCF level in order to avoid the introduction of the basis-set superposition error (BSSE). Due to the importance that nucleic-acid base interactions play in DNA and RNA, which are 3-D structures, we present applications of this approach of Self Consistent Field for Molecular Interactions (SCF-MI) to the study of several hydrogen-bonded DNA bases. Nucleic-acid pairs are extensively investigated: structures and energies for both isolated and paired molecules are thoroughly studied. Cs-symmetry equilibrium geometries and binding energies are calculated in the framework of the SCF-MI formalism by using standard basis sets. SCF-MI/3-2 1G stabilisation energies for the studied base pairs lie in the range −22.5/−8.0 kcal/mol, in good agreement with previous, high-level theoretical values. The hydrogen bonding potential energy surface (PES) and propeller twist potentials are also calculated for some of the molecular complexes. The SCF-MI interaction density is used to interpret the nature of the interactions involved in the hydrogen bond formation: structure and stabilisation of the base pairs turn out to be determined mostly by electrostatic interactions. Preliminary calculations on stacked cytosine dimer are also reported. The SCF-MI/3-21G results show agreement with the counterpoise corrected SCF/6-31G** calculations

Hartree-fock Study of Hydrogen-bonded Systems in the Absence of Basis-set Superposition Error the Nucleic-acid Base Pairs

FAMULARI, ANTONINO;
2002-01-01

Abstract

The Roothaan equations have been recently modified for computing molecular interactions between weakly bonded systems at the SCF level in order to avoid the introduction of the basis-set superposition error (BSSE). Due to the importance that nucleic-acid base interactions play in DNA and RNA, which are 3-D structures, we present applications of this approach of Self Consistent Field for Molecular Interactions (SCF-MI) to the study of several hydrogen-bonded DNA bases. Nucleic-acid pairs are extensively investigated: structures and energies for both isolated and paired molecules are thoroughly studied. Cs-symmetry equilibrium geometries and binding energies are calculated in the framework of the SCF-MI formalism by using standard basis sets. SCF-MI/3-2 1G stabilisation energies for the studied base pairs lie in the range −22.5/−8.0 kcal/mol, in good agreement with previous, high-level theoretical values. The hydrogen bonding potential energy surface (PES) and propeller twist potentials are also calculated for some of the molecular complexes. The SCF-MI interaction density is used to interpret the nature of the interactions involved in the hydrogen bond formation: structure and stabilisation of the base pairs turn out to be determined mostly by electrostatic interactions. Preliminary calculations on stacked cytosine dimer are also reported. The SCF-MI/3-21G results show agreement with the counterpoise corrected SCF/6-31G** calculations
2002
Springer Netherlands, Kluwer Academic Publishers
9780306469510
9780792367086
Hydrogen-bonded Systems; Nucleic-acid Base Pairs; Basis Set Superposition Error free interaction potential
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/667594
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