Table 2. Summary of diffraction data and structure refinement statistics.

	SAM-bound	SAH-bound	Apo (V66W/E67P)
Diffraction data
Wavelength (Å)	0.9793	0.9792	0.9792
Space group	P1	P1	I23
Cell parameters
a (Å)	50.27	49.93	168.49
b (Å)	64.10	63.99	168.49
c (Å)	79.27	80.27	168.49
α (°)	90.10	90.26	90
β (°)	93.27	93.38	90
γ (°)	96.61	96.79	90
Resolution (Å)	43.32–2.10	49.49–2.09	37.68–3.55
	(2.15–2.10)*	(2.14–2.09)	(3.68–3.55)
Observed reflections	213,131	108,874	59,066
Unique reflections (I/σ(I) > 0)	51,008	54,989	9792
Average redundancy	4.2 (4.2)	2.0 (2.0)	6.0 (6.3)
Average I/σ(I)	9.5 (1.8)	6.1 (1.7)	7.9 (1.5)
Completeness (%)	88.5 (59.6)	94.8 (78.5)	99.8 (100.0)
Rmerge (%)†	12.7 (84.1)	10.5 (54.0)	16.8 (81.3)
CC1/2	0.995 (0.602)	0.993 (0.678)	0.992 (0.686)
Refinement and structure model
Reflections [Fo ≥ 0σ(Fo)]
Working set	48,879	52,979	9236
Test set	2,018	1,995	485
Rwork/Rfree (%)‡	18.8 / 23.9	16.6 / 20.7	22.5/27.4
No. of protein atoms	7,005	7,176	3843
No. of ligand atoms	108	104	–
No. of water atoms	427	598	–
Average B factor (Å2)
All atoms	29.6	26.5	93.2
Protein	29.4	26.0	93.2
Ligand	22.9	16.3	–
Water	31.1	32.1	–
RMSD
Bond lengths (Å)	0.008	0.007	0.008
Bond angles (°)	1.0	0.9	1.2
Ramachandran plot (%)
Favored	96.8	97.6	94.3
Allowed	3.2	2.4	5.7
Disallowed	0.0	0.0	0.0

*Numbers in parentheses refer to the highest-resolution shell.

†R_merge = ∑_hkl∑_i|I_i(hkl)_i − 〈I(hkl)〉|/∑_hkl∑_iI_i(hkl).

‡R factor = ||F_o| − |F_c||/|F_o|.