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Binding of ligands to a one‐dimensional heterogeneous lattice. III. Kinetic model and relaxation study of the interaction of tilorone with DNA and polynucleotides
Author(s) -
Sturm Jean
Publication year - 1982
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.360210613
Subject(s) - polynucleotide , intercalation (chemistry) , chemistry , kinetic energy , nucleic acid , dna , crystallography , kinetics , relaxation (psychology) , polymer chemistry , stereochemistry , inorganic chemistry , biochemistry , social psychology , psychology , physics , quantum mechanics
A temperature‐jump relaxation study of the interaction of tilorone with different polynucleotides and DNA has been performed. A single relaxation time, attributed to the intercalation step, has been observed in the case of poly[d(A‐T)]·poly[d(A‐T)], poly[d(A‐C)]·poly[d(G‐T)], poly[d(G‐C)]·poly[d(G‐C)], and poly(dG)·poly(dC). No intercalation into poly(dA)·poly(dT) occurs, and the interaction with poly(dG)·poly(dC) is different from what is observed with the other intercalating homopolymers. Refinement of the binding model is suggested from the analysis of the kinetic data. The relaxation curves obtained with DNA are well simulated based on a binding mechanism where DNA is considered a heterogeneous lattice and each type of site behaves as if it were located in the corresponding homopolymer. Poly(dA)·poly(dT) shows a unique behavior: studies of the effects of concentration and temperature indicate that tilorone acts as a probe of a process involving the polynucleotide alone. This process appears to be related to the dynamic structure of the nucleic acid and is detectable only when the bound dye is not intercalated.