DNA Polymorphism as an Origin of Adenine-Thymine Tract Length-Dependent Threading Intercalation Rate
Artikel i vetenskaplig tidskrift, 2008

Binuclear ruthenium complexes that bind DNA by threading intercalation have recently been found to exhibit an exceptional kinetic selectivity for long polymeric adenine-thymine (AT) DNA. A series of oligonucleotide hairpin duplexes containing a central tract of 6-44 alternating AT base pairs have here been used to investigate the nature of the recognition mechanism. We find that, above a threshold AT tract length corresponding to one helix turn of B-DNA, a dramatic increase in threading intercalation rate occurs. In contrast, such length dependence is not observed for rates of unthreading. Intercalation by any mechanism that depends on the open end of the hairpin was found not to be important in the series of oligonucleotides used, as verified by including in the study a hairpin duplex cyclized by a copper-catalyzed "click" reaction. Our observations are interpreted in terms of a conformational pre-equilibrium, determined by the length of the AT tract. We finally find that mismatches or loops in the oligonucleotide facilitate the threading process, of interest for the development of mismatch-recognizing probes. © 2008 American Chemical Society.


Pär Nordell

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Fredrik Westerlund

Köpenhamns universitet

Anna Reymer

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Afaf El-Sagheer

University of Southampton

Suez Canal University

T. Brown

University of Southampton

Bengt Nordén

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Per Lincoln

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Journal of the American Chemical Society

0002-7863 (ISSN) 1520-5126 (eISSN)

Vol. 130 44 14651-14658





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