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Glycosaminoglycan and DNA Binding Induced Intra‐ and Intermolecular Exciton Coupling of the bis ‐4‐Aminoquinoline Surfen
Author(s) -
Zsila Ferenc
Publication year - 2015
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.22471
Subject(s) - chemistry , circular dichroism , intermolecular force , chirality (physics) , intercalation (chemistry) , stereochemistry , macromolecule , dna , crystallography , molecule , biophysics , biochemistry , organic chemistry , biology , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
Despite the diverse biological activities of the glycosaminoglycan (GAG) antagonist surfen, the molecular details of its interaction with biomacromolecules remain poorly understood. Therefore, heparin and DNA binding properties of surfen were studied by circular dichroism (CD) and UV absorption spectroscopy methods. High‐affinity ( K a ~ 10 7 M ‐1 ) association of surfen to the chiral heparin chain gives rise to a characteristic biphasic CD pattern due to the conformational twist of the aminoquinoline moieties around the central urea bridge. At higher drug loading, intermolecular stacking of surfen molecules alters the induced CD profile and also provokes strong UV hypochromism. In contrast to the right‐handed heparin template, binding of surfen to the left‐helicity chondroitin sulfate chains produces inverted CD pattern. Large UV hypochromism as well as polyphasic induced ellipticity bands indicate that surfen intercalates between the base pairs of calf‐thymus DNA. Extensive CD spectroscopic changes observed at higher drug binding ratios refer to cooperative binding interactions between the intercalated drug molecules. The inherent conformational flexibility of surfen demonstrated here for the first time is important in its binding to distinct macromolecular targets and should be considered for rational drug design of novel GAG antagonists. Chirality 27:605–612, 2015 . © 2015 Wiley Periodicals, Inc.