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Quantum‐mechanical study of the hypochromic effect in polynucleotides. Intra‐ and interstrand interaction contributions
Author(s) -
Danilov V. I.,
Volkov S. N.
Publication year - 1975
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1975.360140609
Subject(s) - chemistry , polynucleotide , excited state , hydrogen bond , monomer , polymer , molecule , quantum mechanics , organic chemistry , physics , biochemistry
The first uv absorption band hypochromism of poly(dA) · poly(dT), poly(dG) · poly(dC), poly(dA), poly(dT), poly(dG), and poly(dC) is calculated with the help of perturbation theory on the basis of monomer characteristics computed by the Pariser‐Parr‐Pople method taking into account all singly excited configurations. The theoretical results obtained are in good agreement with experimental values of hypochromism. The origin of the hypochromic effect in the double‐stranded polynucleotides is investigated. It is shown that intrastrand interactions between the bases make the main contribution to hypochromism (60–76%), while the contribution of the Watson–Crick‐pair formation is small (2–12%). The essential part of hypochromism (22–28%) is due to the interstrand interactions between the bases that are not coupled by hydrogen bonds. The discussion of the experimental data shows that the present theoretical investigation could serve as a basis for the correct treatment of experimental data.