Table 1. Data-collection statistics.

Values in parentheses are for the highest resolution shell.

	Crystal form I	Crystal form II
Detector	MAR CCD	MAR CCD
Beamline	BW7A	X13
Data-collection temperature (K)	100	100
Wavelength (Å)	0.9150	0.8073
Unit-cell parameters (Å)	a = b = 74.70, c = 78.97	a = 44.26, b = 81.99, c = 140.89
Space group	P31 or P32	P212121
Content of the asymmetric unit	2 monomers	2 monomers
Resolution range (Å)	15.0–2.60 (2.69–2.60)	20–1.70 (1.76–1.70)
No. of observed reflections	178588 (20260)	318867 (22384)
No. of unique reflections	15027 (1809)	51851 (5596)
Rmerge†	0.110 (0.763)	0.065 (0.165)
Completeness	100 (100)	90.4 (82.2)
I/σ(I)	24.38 (2.27)	17.35 (6.13)
Redundancy	11.88 (11.20)	6.15 (4.00)

^† R _merge = .