. Author manuscript; available in PMC: 2011 Aug 17.

Published in final edited form as: Biochemistry. 2010 Aug 17;49(32):6856–6865. doi: 10.1021/bi100857g

Table 2.

Single-channel current transition amplitudes for channels formed by different combinations of Ser and Ala gramicidin subunits^a

Subunit A	Subunit B	i_AA (pA)	i_AB (pA)	i_BA (pA)	i_BB (pA)
[Gly², Ser³]gA	gA	1.8	2.1	2.5	3.0
[DAla², Ser³]gA	[DAla²]gA	2.2	2.6	3.0	3.7
[Gly², Ser⁵]gA	gA	1.5	1.8	2.4	3.2
[DAla², Ser⁵]gA	[DAla²]gA	1.7	2.2	2.8	3.5

For the hybrid channel experiments, both subunit types were added to both sides of a planar bilayer membrane. The current transition amplitudes for the asymmetric channel types, i_AB and i_BA, denote the direction of the cation flow (from subunit A to subunit B, and vice versa). The direction of current flow was determined in experiments where the two gA analogues were added asymmetrically, to opposite side of the bilayer (see Fig 6). Conditions: 1.0 M NaCl, DPhPC/n-decane, 200 mV.