Table 2.

Spectral properties of the Cavernularia obesa GFP and its variants

	pH	λabs/λem (nm)	ε (M-1 cm-1)	Φ
Wild-type	5	388/456, 502	47,200 (388 nm)	0.28 (380 nm)
		498/506	23,500 (498 nm)	ND
	7	392/457, 506	8,000 (388 nm)	ND
		499/507	147,300 (498 nm)	0.87 (488 nm)
	9	389/506	2,300 (388 nm)	0.30 (380 nm)
		498/507	163,600 (498 nm)	1.00 (488 nm)
Variant-0	5	390/458, 502	56,500 (388 nm)	0.32 (380 nm)
		498/506	30,800 (498 nm)	ND
	7	392/458, 506	11,000 (388 nm)	ND
		498/507	218,900 (498 nm)	0.73 (488 nm)
	9	390/506	3,300 (388 nm)	0.28 (380 nm)
		498/507	232,000 (498 nm)	1.00 (488 nm)
Variant-1	5	393/458	26,600 (388 nm)	0.44 (380 nm)
		499/507	4,800 (498 nm)	ND
	7	395/460, 504	11,900 (388 nm)	ND
		500/507	68,400 (498 nm)	0.88 (488 nm)
	9	398/504	3,400 (388 nm)	0.29 (380 nm)
		500/507	96,500 (498 nm)	1.00 (488 nm)
Variant-2	5	396/462	20,000 (388 nm)	0.28 (380 nm)
		ND/ND	ND	ND
	7	395/462	17,000 (388 nm)	ND
		497/506	2,300 (498 nm)	ND
	9	398/460, 504	8,900 (388 nm)	0.15 (380 nm)
		496/506	24,700 (498 nm)	0.98 (488 nm)
Variant-3	5	396/462	25,800 (388 nm)	0.33 (380 nm)
		ND/ND	ND	ND
	7	396/463	24,000 (388 nm)	ND
		ND / ND	ND	ND
	9	396/461	11,600 (388 nm)	0.39 (380 nm)
		506/512	43,900 (498 nm)	0.27 (488 nm)
Variant-4	5	397/461	35,200 (388 nm)	0.50 (380 nm)
		ND/ND	ND	ND
	7	397/461	36,200 (388 nm)	ND
		ND/ND	ND	ND
	9	397/462	29,200 (388 nm)	0.44 (380 nm)
		503/509	21,700 (498 nm)	1.00 (488 nm)

λ_abs, absorption maxima; λ_em, fluorescence maxima excited by the λ_abs light; ε, molar absorption coefficient at 388 and 498 nm; Φ, fluorescence quantum yield at 388 and 468 nm; ND, not determined (N = 3).