Nanosecond fluorescence studies of noncovalent interaction of monomeric and dimeric intercalators with DNA

The noncovalent interaction of 2-aminodipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2) and its derivatives, which are potent mutagens isolated from L-glutamic acid pyrolysate, with calf thymus DNA was studied by steady-state and nanosecond fluorescence spectroscopies. The fluorescence of these c...

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Bibliographic Details
Published in:Biochemistry (Easton) 1985-11, Vol.24 (23), p.6401-6405
Main Authors: Itoh, Michiya, Kurokawa, Hiroko, Usui, Mayumi, Ohno, Makiko, Shimoda, Emiyo, Hashimoto, Yuichi, Shudo, Koichi
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Carcinogens - pharmacology
Cattle
DNA - metabolism
Fundamental and applied biological sciences. Psychology
Imidazoles - pharmacology
Interactions. Associations
Intercalating Agents - pharmacology
Intermolecular phenomena
Kinetics
Molecular biophysics
Spectrometry, Fluorescence - methods
Structure-Activity Relationship
Thymus Gland
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Summary:The noncovalent interaction of 2-aminodipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2) and its derivatives, which are potent mutagens isolated from L-glutamic acid pyrolysate, with calf thymus DNA was studied by steady-state and nanosecond fluorescence spectroscopies. The fluorescence of these compounds exhibits static quenching by noncovalent interaction with DNA. Fluorescence lifetimes of the free and intercalated states of these compounds were determined to be 9-10 and 0.5-1 ns, respectively. The bisintercalative effect of the dimeric analogue of Glu-P-2, bis(Glu-P-2)spermine (2GP-SP), to DNA was also investigated. This 2GP-SP, which has two Glu-P-2 moieties at each end of spermine, indicates a strong intramolecular interaction exhibiting remarkable quenching of fluorescence spectrum and lifetime (tau = 3.5 ns) in the absence of DNA. In the presence of DNA, however, the 3.5-ns lifetime component of fluorescence disappeared, and a two-exponential decay of fluorescence (t = approximately 10 and 1.5 ns) was observed at a DNA concentration of more than approximately 0.001 mM P, while the solution containing a very dilute DNA concentration (less than or equal to 0.001 mM P) exhibits a three-component decay of fluorescence (1.5, 3.5, and approximately 10 ns). The potent bis intercalation of two moieties in 2GP-SP with an identical DNA molecule was suggested by the DNA-concentration dependence of these fluorescence lifetimes and their intensity.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00344a013