Donor fluorescence decay analysis for energy transfer in double-helical DNA with various acceptor concentrations.
We studied fluorescence resonance energy transfer between donors and acceptors bound to double-helical DNA. The donor Hoechst 33258 binds to the minor groove of DNA and the acceptor propidium iodide (PI) is an intercalator. The time-resolved donor decays were measured in the frequency domain. The donor decays were consistent with a random 1-dimensional distribution of acceptors. The decays were analyzed in terms of three 1-dimensional models: a random continuous acceptor distribution; acceptors placed on discrete lattice sites; and a cylindrical model with the acceptor in the center, and the donors on a cylinder surface. The data were well described by all three models. Interpretation in terms of continuous distribution of acceptors revealed a minimum donor to acceptor distance of 13 A, which is 3 bp from the center of Hoechst 33252. These results suggest that PI is excluded from the 4 bp covered by Hoechst 33252 when it is bound to the minor groove of DNA.
Murata
S I
SI
Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore School of Medicine, 21201, USA.
Kuśba
J
J
Piszczek
G
G
Gryczynski
I
I
Lakowicz
J R
JR
D000818:Animals; D006690:Bisbenzimidazole / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D002417:Cattle; D004247:DNA / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D004735:Energy Transfer; D005453:Fluorescence; D006207:Half-Life; D008956:Models, Chemical; D015394:Molecular Structure; D011419:Propidium / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D013050:Spectrometry, Fluorescence / Q000379:methods
D011419:Propidium; D004247:DNA; D006690:Bisbenzimidazole