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Number of binding sites of DNA and polynucleotides with tris(2,2′‐bipyridyl)ruthenium(II) cations
Author(s) -
Stradowski Czeslaw,
Görner Helmut,
Currell Leslie J.,
SchulteFrohlinde Dietrich
Publication year - 1987
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.360260203
Subject(s) - polynucleotide , ruthenium , chemistry , tris , dna , luminescence , nucleotide , nucleic acid , quenching (fluorescence) , aqueous solution , polymer chemistry , stereochemistry , photochemistry , fluorescence , organic chemistry , biochemistry , physics , optoelectronics , quantum mechanics , gene , catalysis
The binding of tris(2,2′‐bipyridyl)ruthenium(II) cations [Ru(bpy) 2+ 3 ] with single‐ and double‐stranded (ss and ds) DNA, and the polynucleotides poly(A), poly(C), poly(G), poly(I), poly(I) · poly(C), and poly(U), was studied in aqueous solution. Steady‐state electrical conductivity measurements with the polynucleotides, ssDNA, and dsDNA reveal that approximately three nucleotides offer one binding site. This may be compared with the ratio [nucleotide]/[Mg 2+ ] of 2.4 : 1 for dsDNA. After laser excitation (353 nm), the luminescence of Ru(bpy) 2+ 3bound to nucleic acids shows two decay components. The contribution of the fast component, which is interpreted as resulting from quenching processes of the absorbed ruthenium complex, exhibits a maximum with increasing [nucleotide]/[Ru(bpy) 2+ 3 ] at a ratio of about three to one. Bound Ru(bpy) 2+ 3can be released from the strand by addition of NaClO 4 [half‐concentration: 2.5 and ≤ 10 m M for poly(U) and dsDNA, respectively].