Table I. Crystallographic data.

Fragment name	1A	Z2B	Cys2
Vimentin residues included	102–138	385–412	328–411
No. of residues per chaina	39	59	84
Diffraction data
Space group	P6222	P3121	I222
Cell constants a × b × c (Å)	56.8 × 56.8 × 58.4	98.8 × 98.8 × 36.5	76.6 × 84.3 × 240.8
Resolution limitsb,c (Å)	50.0–1.4 (1.45–1.40)	35.0–1.9 (1.97–1.90)	35.0–2.3 (2.33–2.30)
No. of independent reflections	11 440 (1122)	15 422 (1604)	34 937 (1159)
Redundancy	10.3 (5.5)	4.0 (3.7)	4.5 (4.0)
Completeness (%)	99.7 (99.6)	99.2 (99.4)	99.5 (99.7)
<I/σ>	17.0 (1.9)	14.6 (3.3)	13.5 (1.8)
Rsymd	0.037 (0.560)	0.063 (0.372)	0.058 (0.405)
Refined model
Protein chains/asymmetric unit	1	2	6
Ordered vimentin residues in each chain	A: 102–138	A: 385–409	A: 328–406
		B: 385–406	B: 328–406
			C: 337–406
			D: 330–407
			E: 337–406
			F: 333–406
No. of solvent molecules	35	194	455
Total no. of non-H atoms	375	1066	4170
Average model B-factor	23.5	31.5	53.8
Rworke	0.197	0.199	0.242
Rfreee,f	0.216 (461)	0.227 (778)	0.262 (1095)
R.m.s.d. bondsg (Å)	0.020	0.017	0.008
R.m.s.d. anglesg (°)	2.0	1.7	1.1

^aBesides the authentic vimentin residues, the 1A fragment contains two extra residues, GlySer, at the N-terminus (see Strelkov et al., 2001). The Z2B chimera includes the GCN4 leucine zipper.

^bData in parentheses are for the highest resolution shell.

^cCys2 crystals exhibited anisotropic diffraction, which extended up to 1.9 Å resolution in the c* direction and to 2.3 Å resolution in the a* and b* directions.

^dR_sym = |I_hi – <I_h>|<I_h>, where I_hi is the ith intensity measurement of a reflection with index h.

^eR = ∑|F_obs – F_calc|/∑F_obs.

^fIn parentheses is the number of randomly selected reflections that were excluded from refinement and used to calculate the ‘free’ R-factor (Brünger and Nilges, 1993).

^gR.m.s.ds from the Engh and Huber standard parameters.