Fluctuation in structure of inclusion complexes of cyclodextrins with fluorescent probes

The lifetime distribution of the fluorescence from inclusion complexes of cyclodextrins with anilinonaphthalenesulfonates (ANSs) was analyzed by time-correlated single-photon counting measurements. The very large width of the lifetime distribution as well as the dependence of the apparent maximum wavelength of the fluorescence on the excitation wavelength indicates that the conformation of the excited TNS molecules in cyclodextrin cavities is distributed within a wide range. These observations indicate a striking similarity between the fluorescence of fluorophores in proteins and that in the inclusion complexes.