Table 2. Structural statistics.

Experimental restraints
Distance restraints A	2522
Intra-residue	456
Inter-residue
Short-range (|i-j| = 1)	702
Medium-range (1< |i-j| <5)	246
Long-range (|i-j| >5)	708
Inter-monomer	410 (2x205)
Dihedral restraints (ϕ/ψ)	176 (2x88)
Structural quality
Coordinate precision (Å) B *
N, Cα, C'	0.35 ± 0.08
Heavy atoms	0.66 ± 0.05
Restraint RMSD C
Distance restraints (Å)	0.015 ± 0.003
Dihedral restraints (°)	0.808 ± 0.102
Deviation from idealized geometry D
Bond lengths (Å)	0.008
Bond angles (°)	1.0
Ramachandran plot (%) E *
Preferred regions	93.4
Allowed regions	6.6
Generously allowed regions	0
Disallowed regions	0
WhatIf analysis F *
1st generation packing	3.218 ± 1.105
2nd generation packing	7.898 ± 2.540
Ramachandran plot appearance	1.245 ± 0.578
Chi-1/Chi-2 rotamer normality	-3.492 ± 0.454
Backbone conformation	2.384 ± 0.614

^A 2412NOE cross peaks out of 2727 were assigned by CYANA. All numbers are given for the symmetric dimer.

^B RMSD of the backbone coordinates to the mean structure.

^C Analyzed by iCING. No distance/dihedral angle restraint was violated by more than 0.3 Å/5°, respectively, in any of the models.

^D PDB validation and deposition server (ADIT).

^E With Procheck.

^F Structure Z-scores, a positive number is better than average.

* For residue 5–57 of the expression construct (RMSD < 2 Å).