Article

Fluorescence lifetime distributions of DNA-4',6-diamidino-2-phenylindole complex.

Instituto di Chimica Biologica, Università di Catania, Italy.
Biochimica et Biophysica Acta (impact factor: 4.66). 01/1990; 993(2-3):174-8. DOI:10.1016/0304-4165(89)90160-8
Source: PubMed

ABSTRACT Time-resolved fluorescence of 4',6-diamidino-2-phenylindole (DAPI) complexes show that for a homogeneous polymer (polyd(AT) or polyd(A).polyd(T)) at high P/D (phosphate/dye) ratio, a single exponential component adequately describes the fluorescence decay. For the AT polymers at low P/D ratio or for native DNA, the decay cannot be described by a single-exponential term. A continuous distribution of lifetime values of Gaussian shape gives a good fit to the decay data. We propose that the lifetime distribution method for the analysis of the fluorescence decay of DNA-DAPI complexes provides a useful method of characterizing the microheterogeneity of site binding.

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Keywords

continuous distribution
 
fluorescence decay
 
Gaussian shape
 
good fit
 
lifetime distribution method
 
lifetime values
 
low P/D ratio
 
single exponential component
 
single-exponential term
 
site binding
 
Time-resolved fluorescence
 
useful method
 

M L Barcellona