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Carcinogen–base stacking and base–base stacking in dCpdG modified by (+) and (−) anti ‐BPDE
Author(s) -
Hingerty Brian E.,
Broyde Suse
Publication year - 1985
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.360241209
Subject(s) - chemistry , conformational isomerism , stacking , dihedral angle , stereochemistry , guanine , dimer , epoxide , adduct , enantiomer , pyrene , carcinogen , base (topology) , base pair , torsion (gastropod) , crystallography , computational chemistry , molecule , dna , nucleotide , organic chemistry , biochemistry , mathematical analysis , hydrogen bond , mathematics , gene , catalysis , medicine , surgery
The low‐energy conformations accessible to dCpdG modified at guanine N 2 via trans epoxide opening by (+) and (−) 7β,8α‐dihydroxy‐9α,10α‐epoxy‐7,8,9,10‐tetrahydrobenzo(a)pyrene ( anti ‐BPDE) have been delineated by minimized semiempirical potential‐energy calculations with all torsion angles flexible. Nearly 4000 trials were made, representing a fairly thorough investigation of the conformation space of the adducts. Carcinogen–base stacked states and base–base stacked conformers were found in the low‐energy regions of both enantiomers. Many ω′, ω, ψ domains accommodate the two types of conformations, with B‐like backbones among the most preferred states in each case. The conformational differences between the two enantiomers on the dimer level reside in subtle distinctions in orientation of the carcinogen–base linkage.