The effect of a distribution of separations upon intramolecular distances in biopolymers, as determined by radiationless energy transfer.
In a fluorescent donor group and a nonfluorescent acceptor group are incorporated into a biopolymer, so that radiationless energy transfer occurs between the two groups, the apparent separation of the groups, as determined by energy transfer, will be influenced by the existence of a distribution of separations. This might arise from the presence of significant localized flexibility at the sites of attachment of the two groups, or from internal flexibility involving the biopolymer itself. If a Gaussian form is assumed for the distribution of separations of the donor and acceptor groups, the efficiency of transfer is dependent upon the width of the distribution, as well as the average distance between the groups. Significant differences may thereby arise between the true average separation and the separation computed from transfer efficiencies by the usual procedures. The deviations are different for transfer efficiencies computed from quantum yields and from decay times. They become more important with increasing width of the distribution of separations and increasing efficiency of transfer. In general, if a distribution of separations is present, the average separation is most reliably computed by procedures which take into account the effects of this distribution.
Albaugh
S
S
Department of Chemistry, University of Maryland, Baltimore, MD 21228.
Lan
J Q
JQ
Steiner
R F
RF
D001704:Biopolymers; D004735:Energy Transfer; D046911:Macromolecular Substances; D008433:Mathematics; D008962:Models, Theoretical; D008968:Molecular Conformation; D013050:Spectrometry, Fluorescence
D001704:Biopolymers; D046911:Macromolecular Substances