Figure 4.

Comparison of two CD TCC and taxol (TXA) pore current traces with peptide (AgA (15) and alamethicim (Alm)) channel currents [9]. AgA (15) is a gramicidin A (gA) analogue having 15 amino acids in its sequence. The upper panel shows triangular-shape conductance events induced by TCC and TXA, both at 90 μM. pH = 5.7, V = 100 mV, filtered at 20 kHz. A single conductance event (pointed by a right arrow) shows all current points (in Origin 8.5 plot) and suggests for a triangular pattern, so does the pore current change spontaneously with time in both increasing and decreasing directions. The lower panel (A) illustrates rectangular-shape conductance events in gA and Alm channels (Ashrafuzzaman et al., 2008). gramicidin A (gA) channel activity was recorded at V = 200 mV and Alm at V = 150 mV and filtered at 2 and 20 kHz, respectively. Current values I_gA = 29 ± 2, 113 ± 5, 243 ± 9, and 386 ± 10 pA, respectively, are the discrete current levels 0, 1, 2, 3, …, etc. in the Alm channel. (B), the point count plots of the current traces through AgA (15) and Alm channels showing peaks at discrete values of conductance. The discreteness in conductance values for the CD pores is missing due to their triangular nature [1,2].