Cyanine dyes as intercalating agents: kinetic and thermodynamic studies on the DNA/Cyan40 and DNA/CCyan2 systems
Cyanine dyes as intercalating agents: kinetic and thermodynamic studies on the DNA/Cyan40 and DNA/CCyan2 systems
Engineering Village 2
2006 Elsevier Inc
Accession number: 8625406
Title: Cyanine dyes as intercalating agents: kinetic and thermodynamic studies on the DNA/Cyan40 and DNA/CCyan2 systems
Authors: Biver, T.1 ; De Biasi, A.1 ; Secco, F.1 ; Venturini, M.1 ; Yarmoluk, S.
Author affiliation: 1 Dipt. di Chimica e Chimica Ind. Pisa Univ., Italy
Serial title: Biophysical Journal
Abbreviated serial title: Biophys. J. (USA)
Volume: 89
Issue: 1
Publication date: July 2005
Pages: 374-83
Language: English
ISSN: 0006-3495
CODEN: BIOJAU
Document type: Journal article (JA)
Publisher: Biophys. Soc
Country of publication: USA
Material Identity Number: B154-2005-008
Abstract: The interaction of cyanines with nucleic acids is accompanied by intense changes of their optical properties. Consequently these molecules find numerous applications in biology and medicine. Since no detailed information on the binding mechanism of DNA/cyanine systems is available, a T-jump investigation of the kinetics and equilibria of binding of the cyanines Cyan40 [3-methyl-2-(1,2,6-trimethyl-4(1H)pyridinylidenmethyl)-benzothiaolium ion] and CCyan2 [3-methyl-2-[2methyl-3-(3-methyl-2(3H)-benzothiazolytidene)-1-propenyl]-benzothiazolium ion] with CT-DNA is performed at 25?C, pH 7 and various ionic strengths. Bathochromic shifts of the dye absorption band upon DNA addition, polymer melting point displacement (?T = 8-10?C), site size determination (n = 2), and stepwise kinetics concur in suggesting that the investigated cyanines bind to CT-DNA primary by intercalation. Measurements with poly(dA-dT)?poly(dA-dT) and poly(dG-dC)-poly(dG-dC) reveal fair selectivity of CCyan2 toward G-C basepairs. T-jump experiments show two kinetic effects for both systems. The binding process is discussed in terms of the sequence D + S &lrarr2; D,S &lrarr2; DSI &lrarr2; DSII, which leads first to fast formation of an external complex D,S and then to a partially intercalated complex DSI which, in turn, converts to DSII, a more stable intercalate. Absorption spectra reveal that both dyes tend to self-aggregate; the kinetics of CCyan2 self-aggregation is studied by T-jump relaxation and the results are interpreted in terms of dimer formation
Number of references: 55
Inspec controlled terms: aggregation - association - biochemistry - dyes - melting - molecular biophysics - polymer melts - proteins - thermodynamics
Uncontrolled terms: cyanine dyes - intercalating agents - binding kinetics - binding thermodynamics - DNA/Cyan40 - DNA/CCyan2 systems - cyanine-nucleic acid interaction - optical properties - binding equilibria - cyanines - Cyan40 [3-methyl-2-(1,2,6-trimethyl-4(1H)pyridinylidenmethyl)-benzothiaolium ion] - CCyan2 [3-methyl-2-[2methyl-3-(3-methyl-2(3H)-benzothiazolytidene)-1-propenyl]-benzothiazolium ion] - bathochromic shifts - dye absorption band - DNA addition - polymer melting point displacement - poly(dA-dT)?poly(dA-dT) - poly(dG-dC)-poly(dG-dC) - self-aggregation - T-jump relaxation - dimer formation - 25 degC
Inspec classification codes: A8715B Biomolecular structure, configuration, conformation, and active sites - A8715D Physical chemistry of biomolecular solutions; condensed states - A8715M Interactions with radiations at the biomolecular level - A8230N Association, addition, and insertion - A8270 Disperse systems
Numerical data indexing: temperature 2.98E+02 K
Treatment: Experimental (EXP)
Discipline: Physics (A)
DOI: 10.1529/biophysj.105.059790
Database: Inspec
Copyright 2005, IEE
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