TABLE 4.

Comparison of relative single channel lifetimes of gramicidin channels having Trp → 1-Me-Trp and Trp → Phe substitutions

Substitution position	Normalized lifetimea
	Trp → 1-Me-Trpb	Trp → Phec
None	1.0	1.0
9	1.1	1.2
11	1.8	2.7
13	1.2	1.0
15	1.3	1.0
9, 11, 13, 15	3.2	0.4d

^aValues relative to lifetime of native gA channels.

^bData from Table 3, measured in 1.0 m CsCl.

^cData from Ref. 27, measured under conditions of 1.0 m NaCl and 200 mV.

^dData from Ref. 75, measured under conditions of 1.0 m CsCl and 200 mV.