Decays of Staphylococcal Nuclease and Melittin

The intensity decays could be fit to the two-decay-time model (Table 5.5). In the absence of DNA, the intensity is dominated by a 0.19-ns component. The decay is nearly unchanged by the presence of poly (dG-dC), except for an increase in the decay time of the short component to 0.6 ns. Substantial changes in the intensity decay are found 

As discussed in Section 5.10. the lifethnes calculated from the phase and modulation at a single frequency are only a arait values. The heterogMems decay of DAPI in water illustrates this effect. For an observaticm wavelength of470 nm and a modulation frequency of 100 MHz, 

It is interesting to compare the frequency responses of Quin-2 and SPQ. Whereas Quin-2 displayed a complex frequency response, the responses of SPQ appear to be mostly single exponentials. The decays of SPQ are simpler than those of Quin-2 bec se the chloride is quenching the entire population of SPQ molecules. Hence, the decay is due to a homogeneous population of fiuorophores. 

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