Estimation of the band structure of DNA on the basis of an ab initioSCF LCAO band structure of polycytosine

Abstract

A minimal basis set ob inirio calculation has been performed for the four nucleotide bases and for the infinite polycytosine chain. The LEMO levels have been corrected using the OAO procedure. Long-rangc correlation effects on the band structure of polyC have been computed using the electron polaron model.Using these calculated quantities and assuming that the other three homopolynucleotides have a similar band structure as polyC, the positions and widths of their valence and exciton bands have been approximated. Finally. by the superposition of the band structures of the homopolynucleotides the physically interesting bands of poly(G-C) and poly(A-T) have been estimated.

Electronic structure of biopolymers and possible mechanisms of chemical carcinogenesis

“…(1 5 ) and (16)] the value of 8.95 --A eV has been applied. (This is the H F value, corrected with the help of the OAO procedure, of a double unit of polyglycine H2N-CO-CH2-NH-CO-CH3 [7] .) Table I gives the two highest filled and lowest unfilled energy bands of polyglycine obtained in the Hartree-Fock approximation.…”

“…These calculations have been supplemented by an approximate determination of the effect of the long-range correlation with the help of the electronic polaron model [ 5 ] and by taking into account the shift of the center of the conduction band of polyC (due to the excitonic correction) using the OAO method [6]. On the basis of the corrected band structure of polyC an estimate of the probable band structures of the three other homopolynucleotides and poly base pairs [poly(A-T) and poly(G-C)] has also been given [7]. We shall outline in this paper the results of a coherent potential approximation (CPA) [ 81 calculation using k-and energy-dependent self-energy for a polymer, namely, for the (SN), and (SN-H), mixed system.…”

Ab-initio band structure of polycytidine; internal charge transfer in DNA

“…In a previous publication [ 11 we have reported an ab-initio SCF LCAO crystal orbital (co) calculation of a cytosine stack. On the basis of the results obtained an estimation of the band structure of DNA has also been performed [2]. As the next step of the systematic investigation of the electronic structure of DNA, we give in the present paper ab-initio band structure calculation results for all four nucleotide base stacks, for the sugar-phosphate chain of DNA, and for a whole cytosine-sugar-phosphate chain (polycytidine).…”