Ba2+ block parameters for KcsA-E71A
| K+ | 0 | 3 µM | 10 µM | 25 µM | 50 µM | 100 µM | 300 µM | 500 µM | 1 mM | 5 mM | 20 mM |
| τf (ms) | 6 (2) | 4.69 (0.04) | 7 (1) | — | — | — | — | 3.3 (0.5) | 4.1 (0.2) | 6 (1) | 6 (0.3) |
| τs (ms) | 15 (1) | 17 (1) | 20 (1) | 31 (1) | 34 (2) | 47 (3) | 96 (2) | 146 (5) | 179.9 (0.2) | 298 (33) | 330 (25) |
| af (s−1) | −69 (7) | −38 (9) | −38 (15) | — | — | — | — | 58 (11) | 38 (4) | 57 (10) | 67 (1) |
| as (s−1) | 93 (5) | 72 (7) | 65 (9) | 32 (1) | 30 (2) | 22 (2) | 10.4 (0.2) | 5.8 (0.3) | 4.71 (0.09) | 2.5 (0.4) | 1.7 (0.2) |
| b (s−1) | 24 (6), 44 (2) | 33 (8) | 26 (6) | 32 (1) | 30 (2) | 22 (2) | 10.4 (0.2) | 63 (11) | 43 (4) | 59 (10) | 69 (1), 107 (7) |
| c (s−1) | 45, 29 (2) | 175 (12) | 127 (27) | 79 (4), 95 (5) | |||||||
| d (s−1) | 18, 7 (6) | 32 (1) | 12 (3) | 6.8 (0.7), 3.0 (0.3) | |||||||
| z (s−1) | 175, 204 (6) | 0 | 0 | 0, 1.6 (0.1) | |||||||
| Rb+ | 1 µM | 2 µM | 10 µM | 20 µM | 100 µM | 200 µM | 1 mM | 20 mM | |||
| τf (ms) | 6 (2) | — | 13.7 (0.9) | 13.1 (0.6) | 11 (2) | 11 (1) | 9 (2) | 4.7 (0.6) | |||
| τs (ms) | 17 (1) | 32 (3) | 78 (16) | 107 (6) | 214 (10) | 338 (29) | 927 (21) | 1,890 (240) | |||
| af (s−1) | −41 (5) | — | 58 (3) | 53 (3) | 34 (8) | 28 (2) | 34 (8) | 162 (29) | |||
| as (s−1) | 73 (5) | 32 (3)1 | 3.0 (0.9) | 2.9 (0.2) | 3.1 (0.1) | 2.1 (0.2) | 0.79 (0.05) | 0.15 (0.02) | |||
| b (s−1) | 32 (9) | 32 (3) | 61 (4) | 56 (3) | 37 (8) | 31 (2) | 34 (8) | 162 (29) | |||
| c (s−1) | 83 (9) | 59 (7) | |||||||||
| d (s−1) | 4.0 (0.5) | 0.75 (0.09) | |||||||||
| z (s−1) | 0 | 0 | |||||||||
| Cs+ | 1 µM | 10 µM | 20 µM | 100 µM | 1 mM | 20 mM | |||||
| τf (ms) | 3.77 (0.05) | — | — | 9 (2) | 6 (1) | 5 (1) | |||||
| τs (ms) | 17.5 (0.4) | 21.4 (0.7) | 27 (2) | 76 (5) | 318 (19) | 1116 (48) | |||||
| af (s−1) | −41 (13) | — | — | 48 (27) | 65 (2) | 110 (34) | |||||
| as (s−1) | 65 (4) | 47 (2) | 37 (3) | 9.5 (0.7) | 1.9 (0.1) | 0.44 (0.05) | |||||
| b (s−1) | 25 (10) | 47 (2) | 37 (3) | 58 (26) | 67 (1) | 110 (34) | |||||
| c (s−1) | 96 (22) | 96 (3) | |||||||||
| d (s−1) | 7.9 (0.8) | 1.8 (0.2) | |||||||||
| z (s−1) | 0 | 0 | |||||||||
| NH4+ | 100 µM | 500 µM | 1 mM | 20 mM | |||||||
| τf (ms) | 6 (1) | — | — | 3 (1) | |||||||
| τs (ms) | 17 (4) | 28.8 (0.5) | 47 (6) | 199 (23) | |||||||
| af (s−1) | −79 (11) | — | — | 125 (42) | |||||||
| as (s−1) | 87 (10) | 34.8 (0.5) | 22 (3) | 3.1 (0.2) | |||||||
| b (s−1) | 7.9 (0.7) | 34.8 (0.5) | 22 (3) | 128 (42) | |||||||
| c (s−1) | 181 (42) | ||||||||||
| d (s−1) | 12.8 (0.6) | ||||||||||
| z (s−1) | 0 |
| K+ | 0 | 3 µM | 10 µM | 25 µM | 50 µM | 100 µM | 300 µM | 500 µM | 1 mM | 5 mM | 20 mM |
| τf (ms) | 6 (2) | 4.69 (0.04) | 7 (1) | — | — | — | — | 3.3 (0.5) | 4.1 (0.2) | 6 (1) | 6 (0.3) |
| τs (ms) | 15 (1) | 17 (1) | 20 (1) | 31 (1) | 34 (2) | 47 (3) | 96 (2) | 146 (5) | 179.9 (0.2) | 298 (33) | 330 (25) |
| af (s−1) | −69 (7) | −38 (9) | −38 (15) | — | — | — | — | 58 (11) | 38 (4) | 57 (10) | 67 (1) |
| as (s−1) | 93 (5) | 72 (7) | 65 (9) | 32 (1) | 30 (2) | 22 (2) | 10.4 (0.2) | 5.8 (0.3) | 4.71 (0.09) | 2.5 (0.4) | 1.7 (0.2) |
| b (s−1) | 24 (6), | 33 (8) | 26 (6) | 32 (1) | 30 (2) | 22 (2) | 10.4 (0.2) | 63 (11) | 43 (4) | 59 (10) | 69 (1), |
| c (s−1) | 45, | 175 (12) | 127 (27) | 79 (4), | |||||||
| d (s−1) | 18, | 32 (1) | 12 (3) | 6.8 (0.7), | |||||||
| z (s−1) | 175, | 0 | 0 | 0, | |||||||
| Rb+ | 1 µM | 2 µM | 10 µM | 20 µM | 100 µM | 200 µM | 1 mM | 20 mM | |||
| τf (ms) | 6 (2) | — | 13.7 (0.9) | 13.1 (0.6) | 11 (2) | 11 (1) | 9 (2) | 4.7 (0.6) | |||
| τs (ms) | 17 (1) | 32 (3) | 78 (16) | 107 (6) | 214 (10) | 338 (29) | 927 (21) | 1,890 (240) | |||
| af (s−1) | −41 (5) | — | 58 (3) | 53 (3) | 34 (8) | 28 (2) | 34 (8) | 162 (29) | |||
| as (s−1) | 73 (5) | 32 (3)1 | 3.0 (0.9) | 2.9 (0.2) | 3.1 (0.1) | 2.1 (0.2) | 0.79 (0.05) | 0.15 (0.02) | |||
| b (s−1) | 32 (9) | 32 (3) | 61 (4) | 56 (3) | 37 (8) | 31 (2) | 34 (8) | 162 (29) | |||
| c (s−1) | 83 (9) | 59 (7) | |||||||||
| d (s−1) | 4.0 (0.5) | 0.75 (0.09) | |||||||||
| z (s−1) | 0 | 0 | |||||||||
| Cs+ | 1 µM | 10 µM | 20 µM | 100 µM | 1 mM | 20 mM | |||||
| τf (ms) | 3.77 (0.05) | — | — | 9 (2) | 6 (1) | 5 (1) | |||||
| τs (ms) | 17.5 (0.4) | 21.4 (0.7) | 27 (2) | 76 (5) | 318 (19) | 1116 (48) | |||||
| af (s−1) | −41 (13) | — | — | 48 (27) | 65 (2) | 110 (34) | |||||
| as (s−1) | 65 (4) | 47 (2) | 37 (3) | 9.5 (0.7) | 1.9 (0.1) | 0.44 (0.05) | |||||
| b (s−1) | 25 (10) | 47 (2) | 37 (3) | 58 (26) | 67 (1) | 110 (34) | |||||
| c (s−1) | 96 (22) | 96 (3) | |||||||||
| d (s−1) | 7.9 (0.8) | 1.8 (0.2) | |||||||||
| z (s−1) | 0 | 0 | |||||||||
| NH4+ | 100 µM | 500 µM | 1 mM | 20 mM | |||||||
| τf (ms) | 6 (1) | — | — | 3 (1) | |||||||
| τs (ms) | 17 (4) | 28.8 (0.5) | 47 (6) | 199 (23) | |||||||
| af (s−1) | −79 (11) | — | — | 125 (42) | |||||||
| as (s−1) | 87 (10) | 34.8 (0.5) | 22 (3) | 3.1 (0.2) | |||||||
| b (s−1) | 7.9 (0.7) | 34.8 (0.5) | 22 (3) | 128 (42) | |||||||
| c (s−1) | 181 (42) | ||||||||||
| d (s−1) | 12.8 (0.6) | ||||||||||
| z (s−1) | 0 |
Blocking parameters were determined at internal 200 mM K+ and 50-mV holding voltage, with the indicated concentrations of monovalent cation in the external solution. Time constants and amplitudes were measured by fitting block-time histograms, and rate constants were derived therefrom. Parameters are reported as mean with SEM in parentheses of three to five single-channel datasets in separate bilayers. Dashes indicate components with negligible PDF amplitude, for which block-time PDF was single exponential. Underlined rate constants are mean values (SE in parentheses) determined by Bayesian analysis of four separate datasets for which no assumption about the value of z was made; those in bold refer to Bayesian analysis using prior distribution for z, as described in Appendix A.
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