Table 1.

Characteristics of selected far-red fluorescent proteins

Fluorescent protein	Quarternary structure	Ex. peaka	Em. peaka	Extinction coefficientb	Quantum yieldc	Peak brightnessd	PDB number
DsRed	tetramer	558	583	75	0.79	59	1GGX
E2-Crimson	tetramer	611	646	59	0.12	7.0
dTomato	dimer	554	581	69	0.69	48
mRFP1	monomer	584	607	50	0.25	13
mCherry	monomer	587	610	72	0.22	16	2H5Q
mPlum	monomer	590	649	41	0.10	4.1	2QLG
AQ143	tetramer	595	655	90	0.04	3.6	4OHS
mRaspberry	monomer	598	625	86	0.15	13
mGrape3	monomer	608	646	40e	0.03	1.2
eqFP578	dimer	552	578	102	0.54	55	3PIB
Katushka2	dimer	588	633	67	0.44	29	3PJ7
eqFP650	dimer	592	650	65	0.24	16	4EDO
eqFP670	dimer	605	670	70	0.06	4.2	4EDS
TagRFP	monomer	555	584	98	0.41	40	3M22
mKate	monomer	585	635	42	0.30	13	3BXB
mKate2	monomer	586	630	50	0.36	18
TagRFP675	monomer	598	675	56	0.08	4.5	4KGF
mNeptune2.5	monomer	599	643	95	0.28	27
mNeptune2.5	monomer	599	643	95	0.28	27
mNeptune	monomer	600	650	67	0.20	13	3IP2
mCardinal	monomer	604	659	87	0.19	17	4OJ0, 4OQW
TagRFP657	monomer	611	657	34	0.10	3.4

^aExcitation and emission maxima in nm.

^bMaximum extinction coefficient per chromophore in mM⁻¹cm⁻¹ measured by the alkali denaturation method.

^cQuantum yield of fluorescence.

^dCalculated as peak extinction coefficient per chain in mM⁻¹cm⁻¹ multiplied by quantum yield.

^eAfter photoactivation by 470 nm light. See text for references. FPs are grouped into DsRed and eqFP578 clades. Within each clade, they are ordered first by quarternary structure then by excitation peak.