Linear and circular dichroism characterization of thionine binding mode with DNA polynucleotides
Artikel i vetenskaplig tidskrift, 2018

The binding mode of thionine (3,7-diamino-5-phenothiazinium) with alternating and non-alternating DNA poly nucleotides at low binding ratios was conclusively determined using linear and circular dichroism spectroscopies. The binding to [poly(dG-dC)](2) and poly(dG).poly(dC) was purely intercalative and was insensitive to ionic strength. Intercalative binding to [poly(dA-dT)](2) is observed at low ionic strength, but a shift of some dye to an non-intercalative mode is observed as the background salt concentration increases. With poly(dA).poly(dT), intercalative binding is unfavourable, although some dye molecules may intercalate at low ionic strength, and groove binding is strongly promoted with increasing concentration of background salt. However, stacking with bases is observed with single-stranded poly(dA) and with triplex poly(dT).poly(dA).poly(dT) which suggests that the unusual structure of poly(dA). poly(dT) precludes intercalation. Thionine behaves similarly to the related dye methylene blue, and small differences may be attributed either to the ability of thionine to form H-bonds that stabilize intercalation or to its improved stacking interactions in the basepair pocket on steric grounds.

DNA binding

Intercalation

Phenothiazine dyes

Minor groove binding

Författare

Eimer Tuite

Newcastle University

Bengt Nordén

Kemi och kemiteknik, Kemi och biokemi, Fysikalisk kemi

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

1386-1425 (ISSN)

Vol. 189 86-92

Ämneskategorier

Fysikalisk kemi

DOI

10.1016/j.saa.2017.07.064

PubMed

28800432