Table 1 Spectral and Kinetic Constants of Truncation and Point Mutants of Arabidopsis PhyB.

Mutation^a	Absorption maxima^b (nm)		Photoconversion rate^c,d,e (min⁻¹)		Therm rev^c,d,f (x1000 min⁻¹)
Mutation^a	Pr	Pfr	Pr ⇒ Pfr	Pfr ⇒ Pr	Pfr ⇒ Pr
*Domain Truncations*
PΦB
1–450	658	707	0.72^g	0.11 (±0.02)	10.5 (±0.1)
1–624	664	724	0.98 (±0.03)	2.45 (±0.04)	7.91 (±0.02)
1–908^h	665	724	k₁ 2.1 (±0.3)	2.6 (±0.2)	320 (±20)
1–908^h	665	724	k₂ 0.47 (±0.05)		34 (±3)
FL^h,i	664	725	k₁ 1.1		410
FL^h,i	664	725	k₂ 0.12		40
PCB
1–450	643	693	1.04 (±0.05)	0.38 (±0.02)	38.4 ( ± 0.1)
1–624	651	714	1.35 (±0.04)	3.52 (±0.03)	0.52 (±0.01)
1–908	651	714	1.20 (±0.08)	3.52 (±0.06)	29.9 (±0.3)
*NTE Truncations*
10–624	665	724	0.86 (±0.04)	2.43 (±0.01)	9.54 (±0.02)
20–624	665	724	0.82 (±0.09)	2.52 (±0.05)	10.1 (±0.1)
30–624	665	724	0.84 (±0.03)	2.54 (±0.07)	7.7 (±0.5)
41–624	665	725	0.88 (±0.03)	2.60 (±0.06)	6.50 (±0.02)
46–624	666	725	10.8 (±0.1)
51–624	664	723	1.1 (±0.1)	2.53 (±0.06)	16.2 (±0.1)
55–624	665	724			14.9 (±0.1)
56–624	665	723			32.3 (±0.1)
57–624	665	722	0.97 (±0.05)	2.35 (±0.09)	50.1 (±0.1)
59–624	664	719			91.8 (±0.3)
60–624	665	720	1.09 (±0.02)	2.39 (±0.06)	85 (±1)
65–624	666	717	1.18 (±0.09)		143 (±1)
70–624	665	717	1.05 (±0.06)	2.28 (±0.03)	146 (±1)
80–624	664	717	1.17 (±0.03)	2.3 (±0.1)	169 (±1)
90–624	664	717	1.3^g	2.5^g	163 (±1)
100–624	664	717	0.99 (±0.05)	2.2 (±0.2)	134 (±1)
*PSM Point Mutants*
S55A,K56A	666	725			16.3 (±0.1)
Q59A,Q60A	666	721			35.5 (±0.1)
Y61A,T62A	665	725			7.53 (±0.01)

^aData were collected from PhyB containing the indicated residues after removal of the N-terminal 6His-TEV tag.
^bMaxima of the Q absorption band. Pfr maxima were identified from difference spectra generated by subtracting red-irradiated from dark-adapted samples.
^cCalculated from the global fit of absorption at 640 nm, 650 nm, 660 nm, 670 nm, 700 nm, 710 nm, 720 nm, 730 nm, and 740 nm as a function of time using the equation: Abs = ΔAbs_total•exp(−k•Time) + Abs_initial.
^dValues in parentheses represent the average of three technical replicates (±SD).
^eFluence rate was calibrated to 12 μmol•m⁻²•s⁻¹ at the intersecting spectrophotometric light path.
^fFluence rate was calibrated to a nominal 0.465 μmol•m⁻²•s⁻¹ for each measurement.
^gAverage of two technical replicates.
^hPr ⇒ Pfr photoconversion, Pfr ⇒ Pr photoconversion, and/or thermal reversion were expressed as the sum of two exponentials using the equation: Abs = ΔAbs_total1•exp(−k₁*Time) + ΔAbs_total2•exp(−k₂•Time) + Abs_initial.
ⁱData were collected from a single sample.

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