Table 1.

Data Refinement and Statistics

	Apo AnsA	Complexed
		Native AnsA	AnsA[T162A]
	APOM	CNATM	CT162A
Data Collectiona
Space group	P21	P21	P21
Cell dimensions
a, b, c (Å)	57.8, 151.6, 87.1	90.3, 89.8, 93.1	90.5, 89.8, 93.3
α, β, γ (°)	90.0, 88.6, 90.0	90.0, 117.0, 90.0	90.0, 117.1, 90.0
Beamline	ID22, SER-CAT	ID22, SER-CAT	BM22, SER-CAT
Resolution range(Å)	50.0-1.88 (1.93-1.88)	50.0-1.90 (1.97-1.90)	50.0-1.82 (1.89-1.82)
Wavelength(Å)	1.01259	1.01259	0.97923
No. of reflections
Measured	468,621	338,886	377,415
Unique	116,888	95,017	119,400
Rsym(%)b	8.0 (31.0)	8.4 (24.6)	8.0 (29.8)
Completeness(%)	96.2 (85.8)	90.6 (81.3)	99.7 (98.8)
Redundancy	4.0 (3.6)	3.6 (3.2)	3.2 (2.5)
I/σ(I)	18.2 (4.4)	17.9 (5.0)	15.7 (2.4)
Refinement
Resolution range(Å)	50.0-1.89	50.0-1.90	50.0-1.82
No. of reflection(F>0σ(F))	115,353	89,743	115,053
Rwork(%)c	18.4	22.3	20.9
Rfree(%)d	20.7	26.4	22.6
No. of atoms
Protein	10,200	9,589	10,013
Ligand/ion	72	159	136
Water	561	575	515
Average B factors(Å2)
Protein	27	20	26
Ligand	39	15	22
Water	37	24	32
Root mean square deviations from ideal values
Bond lengths(Å)	0.007	0.013	0.005
Bond angles(degrees)	1.5	1.4	1.4
Residues from Ramachandran plot
Most favored(%)	92.2	92.1	91.3
Additional allowed(%)	7.4	7.4	7.9
Generously allowed(%)	0.4	0.5	0.7
Contents of structure e
Chain A	2–280, 287–337	3–17, 40–279, 288–336	3–19, 25–280, 286–336
Chain B	3–280, 287–337	−4–13, 28–280, 288–337	−5–19, 28–280, 287–337
Chain C	2–280, 286–337	3–13, 34–280, 288–336	3–18, 25–280, 286–337
Chain D	1–280, 287–337	−5–13, 30–279, 288–336	−5–19, 25–280, 288–337
PDB code	2P2D	2P2N	2HIM

^aHighest resolution shell is shown in parenthesis.

^bRsym = Σ|(I−<I>)|IΣ(I), where I is the observed intensity.

^cRwork = Σ||Fobs|−|Fcalc|| / Σ|Fobs|, where Fobs and Fcalc are observed and calculated structure factors.

^dRfree is the R value obtained for a test set of reflections consisting of randomly selected 5% subset of the data set excluded from refinement.

^eResidues with negative numbers derive from the 6 × His tag.