TABLE 2.
Average fluorescence lifetimes of BpyFL in homo- and hetero-oligomers at varying percent of the fluorescent label
Proteoliposome preparations containing the same protein and lipid concentration, while varying the molar fraction of PopDBpyFL and either PopD or PopB (see Fig. 3), were analyzed using frequency-domain fluorescence spectroscopy as described previously (14). Phase-Delay and Modulation-Ratio data points for each individual sample were fit to a double-exponential decay model. Addition of a third exponential decay component did not significantly improved the fit. The table summarizes the Intensity weighted (〈τ〉I) and Amplitude weighted (〈τ〉A) average fluorescence lifetimes derived from each individual best fit (in nanosecond time units), as well as the reduced chi-squared (χ2) goodness of fit test parameter.
| % PopDBpyFL in sample | 100 | 90 | 80 | 70 | 60 | 50 | 40 | 30 | 20 | 10 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Plus PopB | 〈τ〉I | 4.8 | 4.9 | 5.1 | 4.7 | 5.2 | 5.2 | 5.4 | 5.3 | 5.5 | 5.6 |
| 〈τ〉A | 3.2 | 3.2 | 3.6 | 3.2 | 3.9 | 4.0 | 4.5 | 4.7 | 5.1 | 5.3 | |
| χ2 | 5 | 5 | 5 | 5 | 3 | 3 | 2 | 1 | 1 | 1 | |
| Plus PopD | 〈τ〉I | 4.8 | 4.7 | 5.1 | 4.8 | 4.6 | 4.7 | 4.6 | 4.7 | 4.9 | 5.2 |
| 〈τ〉A | 3.3 | 3.2 | 3.6 | 3.3 | 3.2 | 3.4 | 3.4 | 3.7 | 4.3 | 4.9 | |
| χ2 | 3 | 3 | 5 | 3 | 2 | 2 | 2 | 1 | 1 | 1 | |