TABLE 2.

Acrylamide quenching of gramicidin fluorescence

Gramicidin conformation	KSV* (M−1)	kq (×10−9)† (M−1 s−1)
Nonchannel	1.41 ± 0.11	0.51
Channel	0.95 ± 0.06	0.55

Concentration of POPC was 0.11 mM and the ratio of gramicidin to POPC was 1:50 (mol/mol). The excitation wavelength was 295 nm; emission was monitored at 334 nm. See Materials and Methods for other details.

^*Calculated using Eq. 3. The quenching parameter shown represents the mean ± standard error of multiple independent measurements whereas quenching data shown in Fig. 6 are from representative experiments.

^†Calculated using mean fluorescence lifetimes from Table 1 and using Eq. 3.