Table 2. Structural statistics for NMR solution structures of Gal-7 in the P4 cis-state in the absence (apo-Gal-7) and presence of lactose (10 mM, holo-Gal-7).
| Parameter | apo-Gal-7 | holo-Gal-7 |
|---|---|---|
| Constraints per monomer | ||
| Intramolecular | ||
| NOE distance restraints (total) | 1659 | 1688 |
| Average number of NOE restraints per residue | 12 | 12 |
| Long-range (|i−j| > 4) | 511 | 525 |
| Hydrogen bonds | 69 | 69 |
| RDC | 67 | 67 |
| Dihedral angle restraints | 131 | 131 |
| Intermolecular | ||
| NOE distance restraints (total) | 18 | Interface: 24 Gal-7/lactose: 10 |
| Hydrogen bonds | 6 | 6 |
| Ramachandran statistics | ||
| Most-favorable region (%) | 80.7 | 73.7 |
| Additionally allowed region (%) | 16.7 | 23.2 |
| Generously allowed region (%) | 2.2 | 2.2 |
| Disallowed region (%) | 0.4 | 0.9 |
| RMSD to the mean structure for the backbone atoms (Å) | 0.6 | 0.8 |
| RMSD to the mean structure for non-hydrogen atoms (Å) | 1.12 | 1.45 |
Structural statistics are essentially the same for Gal-7 in the P4 trans-state, albeit with several fewer NOEs and other constraints observed for N-terminal residues through L9.