Table 1. Diffraction data and refinement statistics.

Values in parentheses are for the highest resolution shell.

	Oxidized form 1	Oxidized form 2	Reduced form 1	Reduced form 2
Diffraction data
Diffraction source	BL17A, PF	BL17A, PF	BL5A, PF	BL5A, PF
Wavelength ()	0.91	0.91	0.80	0.90
Temperature (K)	100	100	100	100
Detector	ADSC Q270	ADSC Q270	ADSC Q315	ADSC Q315
Space group	P212121	P212121	P212121	P212121
a, b, c ()	32.3, 39.3, 61.0	33.6, 51.2, 55.1	33.6, 38.9, 60.6	33.7, 51.3, 55.3
, , ()	90, 90, 90	90, 90, 90	90, 90, 90	90, 90, 90
Resolution range ()	500.83 (0.840.83)	500.93 (0.950.93)	500.76 (0.770.76)	500.95 (0.970.95)
Total No. of reflections	1130607	410023	1237307	423970
No. of unique reflections	72789	63824	99196	58020
Completeness (%)	98.2 (82.3)	98.8 (96.7)	99.8 (97.3)	95.8 (87.0)
Multiplicity	15.5 (10.8)	6.4 (3.5)	12.5 (6.5)	7.3 (3.3)
I/(I)	59.8 (7.6)	50.9 (3.5)	67.4 (4.1)	54.8 (2.3)
R r.i.m. † (%)	8.9 (37.4)	6.8 (43.5)	7.1 (38.6)	8.4 (43.9)
Overall B factor from Wilson plot (2)	6.2	8.4	6.5	8.8
Refinement
Resolution range ()	500.83	500.93	500.76	500.95
Final R cryst (%)	10.8	12.9	10.6	13.9
Final R free (%)	12.7	16.9	13.2	18.1
No. of non-H atoms
Protein	867	898	862	893
Ca2+	2		2
HEPES	15
Acetate		4		4
Haem	43	47	51	43
Water	214	211	252	200
No. of H atoms
Protein	416	232	419	150
Haem	20	13	17	2
Average B factors (2)
Protein	10.0	15.3	9.7	16.1
Haem	9.6	12.5	9.1	12.8
Ca2+	6.4		5.9
HEPES	12.4
Acetate		15.6		14.9
Water	18.1	24.6	18.3	28.6
Ramachandran plot
Most favoured (%)	90.9	92.2	92.2	93.5
Allowed (%)	9.1	7.8	7.8	6.5

^† R _r.i.m. = , where N(hkl) is the data multiplicity.