Table 1.

In vitro properties of purified NCaMP7 indicator compared to GCaMP6s.

Properties			Proteins
			NCaMP7			GCaMP6s
			apo		sat	apo	sat
Abs/Exc maximum (nm)			402/406		509/512	402/ND	500/ND
Emission maximum (nm)			520		522	518	515
Quantum yield a			0.048 ± 0.003		0.52 ± 0.03	0.11 ± 0.01	0.61
ε (mM−1 cm−1) b			46.6 ± 2.7		110.0 ± 7.3	33.3 ± 0.6	77 ± 3
Brightness (%) c			6.5		179	8.3	107
ΔF/F (fold)		0 mM Mg2+	89 ± 27			43 ± 6
		1 mM Mg2+	27 ± 3			46 ± 24
pKa			5.43 ± 0.09 6.62 ± 0.09	6.18 ± 0.21		9.6 ± 0.3	6.16 ± 0.08
Kd (nM) d	0 mM Mg2+		96 ± 5 (n = 2.2 ± 0.3)			144±3 (n = 3.5 ± 0.2)
	1 mM Mg2+		125 ± 7 (n = 1.8 ± 0.2)			227.3 ± 0.2
kobs (s−1) e			0.54 ± 0.02			0.49 ± 0.05
koff (s−1) f	k1 (contrib., %)		0.89 ± 0.01 (78 ± 1)			0.69 ± 0.01
	k2 (contrib., %)		0.11 ± 0.01 (22 ± 1)
t1/2, s g			1.1 ± 0.1			1.01 ± 0.04

^a mEGFP (quantum yield, QY = 0.60 ref. [25]) and mTagBFP2 (QY = 0.64 ref. [26]) were used as reference standards for 500–509- and 402-nm absorbing states, respectively. ^b Extinction coefficient was determined by alkaline denaturation. ^c Brightness was normalized to mEGFP, with a QY of 0.60 and an extinction coefficient of 53.3 ± 3.6 mM⁻¹cm⁻¹. ^d Hill coefficient is shown in brackets. ^e The observed association rates were determined at 300 nM Ca²⁺ concentration from association kinetics curves (Figure 1f). GCaMP6f had k_obs value of 1.28 ± 0.03 sec⁻¹. ^f k_off values were estimated from calcium dissociation curves (Figure 1f) using mono or double exponential decay fitting with individual exponent contributions shown in the brackets. GCaMP6f had a k_off value of 1.89 ± 0.01 s⁻¹. ^g GCaMP6f had a t_off value of 0.37 ± 0.04 s. ND, not determined.