Table 6. Activity of CAI-1 ester analogs in mutant CqsS receptors.
| Compound | wild-type CqsS | CqsS C170A | CqsS C170Y | |||
|---|---|---|---|---|---|---|
| EC50 (nM)a | % Responseb | EC50 (nM)a | % Responseb | EC50 (nM)a | % Responseb | |
| (S)-CAI-1, 1 | 62±3 | 100±4 | 72±21 | 100±44 | >50,000 | 20c |
| C8-CAI-113 | 9,400±1,600 | 83±46 | 2,100±940 | 61±70 | 260±34 | 100±8 |
| C8-ester, 9 | 180±170 | 108±4 | 110±22 | 99±34 | >50,000 | 66c |
| 4-Ph-ester, 37 | 1,100±270 | 59±22 | >50,000 | 16c | >50,000 | 22c |
| 5-Ph-ester, 38 | 231±15 | 93±6 | 180±33 | 83±29 | >50,000 | 19c |
| 3-Cy-ester, 39 | 310±51 | 82±10 | 790±220 | 73±28 | 420±96 | 93±14 |
| 4-Cy-ester, 40 | 84±6 | 97±6 | 360±84 | 77±32 | 960±320 | 51±48 |
| 5-Cy-ester, 41 | 190±27 | 95±9 | 1,000±180 | 101±53 | 11,000±9,800 | 66±57 |
a
Values determined using standard light-based agonist bioassay with the designated CqsS mutant strain, see Supporting Information. All EC50 values are the mean of triplicate analyses with the range defining the 95% confidence interval.
b
Percent maximal bioluminescence, with respect to CAI-1, which is set at 100%. The range defining the 95% confidence interval.
c
The maximal % response at the maximum concentration tested (50,000 nM).