Table 1.

Characterization of the energy-minimized NMR structure of  mPrP(121–231)

Quantity	20 conformers	Mean structure*
Number ≥0.1 Å	2.8  ±  1.6	0
Maximum (Å)	0.10  ±  0.0	0.08
Residual dihedral angle constraint violations
Number ≥1.5 deg.	1.7  ±  1.0	0
Maximum, deg.	1.9  ±  0.3	1.3
AMBER energies, kcal/mol
Total	−5,061  ±  67	−4,777
Van der Waals	−330  ±  19	−348
Electrostatic	−5,679  ±  73	−5,303
rms deviation from ideal geometry
Bond lengths, Å	0.0078  ±  0.002	0.0074
Bond angles, deg.	2.33  ±  0.05	1.62
Peptide bonds, deg.	9.7  ±  2.3	10.7
rms deviation to the averaged coordinates, Å
N, Cα, C′ (124–166, 172–226)	0.8  ±  0.1
Same plus best defined side chains†	0.8  ±  0.1

mPrP(121–231) was studied in aqueous solution containing 0.8 mM protein, pH = 4.5, T = 20°C. The structure determination was based on sequence-specific assignments for 98% of all ¹H, ¹³C, and ¹⁵N nuclei. The missing ¹H assignments include all resonances of Asp-167, the backbone resonances of Gln-168, ¹H^N of Tyr-169, Ser-170, and Asn-171, the nonaromatic resonances of Phe-175, and the side-chain resonances of Glu-220. The input for the final structure calculation consisted of 1,592 NOE upper distance limits (388 intraresidual, 428 sequential, 413 medium range, 363 long range) and 229 dihedral angle constraints. The average residual target function value for the 20 best DYANA conformers was 1.02 ± 0.48 Ų. 

^*The energy-minimized mean structure differs from the average of the atom coordinates of the 20 conformers by a rms deviation of 0.5 Å calculated for the backbone atoms of residues 124–166 and 172–226. 

^†Best-defined side chains are those with a displacement of the heavy atoms smaller than 1.0 Å and include residues 130, 132–134, 137, 139, 141, 146, 149, 153, 158–161, 178–184, 188–192, 199, 201–203, 205–207, 209, 210, and 213–216.