Table 1. Data-collection statistics.

Values in parentheses are for the last shell.

	Mg2+ present	Mg2+ present, SeMet	Mg2+ absent	Mg2+ absent, SeMet
Wavelength (Å)	1.0000	0.97911	1.0000	0.97909
Temperature (K)	100	100	100	100
Space group	P6522	P6522	P212121	P212121
Unit-cell parameters (Å, °)	a = b = 57.7, c = 317.6, α = β = 90, γ = 120	a = b = 57.8, c = 317.7, α = β = 90, γ = 120	a = 77.0, b = 100.3, c = 100.3, α = β = γ = 90	a = 77.1, b = 100.2, c = 100.2, α = β = γ = 90
Resolution (Å)	50–2.3 (2.34–2.30)	50–2.3 (2.38–2.30)	50–3.5 (3.56–3.50)	50–3.9 (3.97–3.90)
Measured reflections	268641	247439	106648	65842
Unique reflections	14966	14932	10184	7460
Completeness (%)	98.8 (99.3)	98.9 (98.8)	99.0 (96.9)	99.3 (98.4)
Redundancy†	18.0 (16.0)	16.6 (14.0)	10.5 (5.2)	8.8 (5.4)
I/σ(I)	68.6 (8.2)	60.0 (7.4)	49.9 (1.9)	41.9 (2.2)
Rmerge‡	0.057 (0.260)	0.083 (0.374)	0.052 (0.406)	0.070 (0.381)

^†Bijvoet pairs were not merged in the calculation of redundancy.

^‡ R _merge = , where I _i is the observed intensity and 〈I _i〉 is the average intensity over symmetry-equivalent measurements.