TABLE 1.
Structural constraints used for solution high resolution three-dimensional structures and statistical analysis of ensembles of apo-S100A1 and apo-S100A1-NO proteins
| Apo-S100A1 | Apo-S100A1-NO | |
|---|---|---|
| NOE distance constraintsa | 2964 | 2916 |
| Intraresidual | 676 | 728 |
| Sequential (|i − j| = 1) | 874 | 774 |
| medium-range (1 < |i − j| < 6) | 818 | 774 |
| Long range (|i − j| > 5) | 394 | 420 |
| Intersubunit | 202 | 220 |
| Torsion angle constraints | ||
| Backbone (ϕ/ψ) | 328 | 312 |
| Residual dipolar couplings 1DHN | ||
| Pf1 phages | 84 | 82 |
| Bicelles (dimyristoyl phosphatidylcholine/dihexanoyl phosphatidylcholine) | 84 | 42 |
| Restraints per residue | 18.6 | 17.9 |
| Structure z scoresb | ||
| First generation quality | 1.36 ± 0.41 | 2.67 ± 0.48 |
| Second generation quality | 4.67 ± 1.16 | 6.68 ± 1.71 |
| Ramachandran plot appearance | −2.76 ± 0.21 | −1.38 ± 0.24 |
| Backbone conformation | −1.47 ± 0.30 | −0.42 ± 0.28 |
| Root mean square z scores | ||
| Bond lengths | 1.17 ± 0.01 | 1.18 ± 0.01 |
| Bond angles | 0.44 ± 0.01 | 0.43 ± 0.01 |
| Side chain planarity | 1.77 ± 0.16 | 1.60 ± 0.13 |
| Improper dihedral distribution | 0.89 ± 0.03 | 0.91 ± 0.03 |
| Ramachandran plotc | ||
| Residues in most favored regions (%) | 92.5 | 93.1 |
| Residues in additional allowed regions (%) | 7.5 | 6.9 |
| Root mean square deviation to the mean structure | ||
| Ordered backbone atoms (3.89) (Å) | 0.34 ± 0.05 | 0.38 ± 0.05 |
| Ordered heavy atoms (3.89) (Å) | 0.64 ± 0.04 | 0.79 ± 0.07 |
a None of the 20 structures in ensembles has a distance violation more than 0.2 Å and dihedral angle violations more than 5°.
b Structures in ensemble were validated by the WhatIf program (38).
c The quality of the ensemble consisting of the 20 lowest energy structures was checked by the PROCHECK-NMR (version 3.4) program (39).