Table 2.
Parameter | Symbol | Units | Type | Fit values |
||||
---|---|---|---|---|---|---|---|---|
Fig. 9 | Figure 9 D–F | Figure 9 G–H | Figure 12 | Figure 13 | ||||
Opsin gain | Γ | unitless | Free | 3.0 | 8.92 | 10.0 | 1.4 | 18.0 |
Opsin decay rate constant | σ | s-1 | Locked | 23.5 | 23.5 | 23.5 | 23.5 | 23.5 |
PDE decay rate constant | ϕ | s-1 | Constrained (ϕ = σ) | 23.5 | 23.5 | 23.5 | 23.5 | 23.5 |
PDE dark activation rate | η | s-1 | Locked | 2395 | 2395 | 2395 | 2395 | 2395 |
cGMP-to-current constant | k | pA2µM-3 | Fixed | 0.02 | 0.02 | 0.02 | 0.02 | 0.02 |
cGMP channel cooperativity | h | unitless | Fixed | 3 | 3 | 3 | 3 | 3 |
Ca2+ extrusion rate constant | β | s-1 | Locked | 9 | 9 | 9 | 9 | 9 |
Fraction of current carried by calcium | q | unitless | Derived | 0.0662 | 0.031 | 0.1125 | 0.0556 | 0.078 |
Maximal cGMP synthesis rate by GC | Smax | s-1 | Derived | 27 153 | 34 950 | 22 752 | 28 784 | 25 677 |
Ca2+ GC affinity | KGC | µM | Locked | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 |
Ca2+ GC cooperativity | m | unitless | Fixed | 4 | 4 | 4 | 4 | 4 |
Ca2+ concentration in darkness | Cadark | µM | Fixed | 1 | 1 | 1 | 1 | 1 |
cGMP concentration in darkness | cGMPdark | µM | Derived | 18.95 | 24.39 | 15.87 | 20.08 | 17.92 |
Dark current | Idark | pA | Measured | −136 | −290 | −80 | −108 | −115 |