Table 2.

Range and speed of optical signals

ConstructV1/2 (mV)Range (mV)τon (ms)τoff (ms)
CC1 (wild type)96 ± 555 ± 1017 ± 3
A154S (S2)53 ± 6−20 to 120 (140)44 ± 640 ± 16
A154D (S2)55 ± 8−10 to 120 (130)68 ± 159 ± 1
D164N (S2)6 ± 2−50 to 60 (110)42 ± 452 ± 5
D164A (S2)45 ± 28*62 ± 1341 ± 4
R168A (S2)67 ± 5−10 to 140 (150)39 ± 1219 ± 3
R217Q (S4)−46 ± 6−130 to 30 (160)25 ± 339 ± 5
R229I (S4)76 ± 1010 to 140 (130)18 ± 17 ± 1
V220T (S4)75 ± 3−10 to 160 (170)13 ± 29 ± 2
V220R (S4)154 ± 935 ± 321 ± 3
R223Q (S4)59 ± 1120 to 100 (80)25 ± 214 ± 1
R217Q/R229I (S4)−42 ± 6−130 to 40 (170)9 ± 310 ± 1
A154D/R217Q/R229I (S2/S4)−15 ± 5−70 to 40 (110)8 ± 19 ± 1
Bongwoori−3 ± 1−60 to 50 (110)10 ± 17 ± 1
ArcLight−17 ± 3−100 to 60 (160)34 ± 429 ± 2
  • The V1/2, range of optical signal, and the weighted time constants at a 100 mV depolarization are listed. The total range is in parentheses. The range is an estimate based on the slope at V1/2. The range was rounded to the nearest 10 mV because it incorporates the error of the inflexion point and the error of the slope (n ≥ 3 for all constructs). No range is listed for CC1, D164A, and V220R because values for the CC1 and V220R constructs are too shifted to positive potentials for a meaningful analysis and the D164A construct did not fit the Boltzmann curve well (Fig. 4B).