Table 3.
Divalent metal ion and water coordinate distances
| Ca2+-S100Ba | Zn2+,Ca2+-S100B | Pnt-Ca2+-S100B | Pnt-Zn2+,Ca2+-S100B | |
|---|---|---|---|---|
| Zn2+ | ||||
| His15 (Nε2) | 2.0 | 2.0 | ||
| His25 (Nε2) | 1.9 | 2.2 | ||
| His85 (Nε2) | 2.0 | 2.0 | ||
| Glu89 (Oε1 or Oε2) | 2.0 | 1.9 | ||
| Ca2+, pseudo-EF hand | ||||
| Ser18 (C=O) | 2.0 | 2.3 | 2.3 | 2.3 |
| Glu21 (C=O) | 2.3 | 2.6 | 2.3 | 2.3 |
| Asp23 (C=O) | 2.6 | 2.5 | 2.3 | 2.3 |
| Lys26 (C=O) | 2.3 | 2.3 | 2.4 | 2.3 |
| Glu31 (Oε1,Oε2) | 2.4, 2.6 | 2.3, 2.5 | 2.5, 2.6 | 2.5, 2.6 |
| H2Ob | 2.2 | 2.5 | 2.5 | 2.3 |
| Ca2+, canonical EF hand | ||||
| Asp61 (OΔ1 or Oδ2) | 2.3 | 2.3 | 2.3 | 2.4 |
| Asp63 (Oδ1 or Oδ2) | 2.6 | 2.4 | 2.4 | 2.5 |
| Asp65 (Oδ1 or Oδ2) | 2.3 | 2.6 | 2.4 | 2.4 |
| Glu67 (C=O) | 2.4 | 2.4 | 2.4 | 2.4 |
| Glu72 (Oε1,Oε2) | 2.3, 2.5 | 2.4, 2.7 | 2.5, 2.6 | 2.3, 2.5 |
| H2Oc | 2.4 | 2.3 | 2.3 | 2.4 |
| Ca2+-bound H2O | ||||
| Asp65 (Oδ1 or Oδ2)c | 2.8 | 2.4 | 2.7 | 2.6 |
| Glu67 (Oε1 or Oε2)b | 2.6 | 2.9 | 2.8 | 2.7 |
All distances are in angstroms and are from nitrogen, oxygen, or Ca2+. Distances between the two Ca2+ ions for the Ca2+-S100B, Zn2+,Ca2+-S100B, Pnt-Ca2+-S100B, and Pnt-Zn2+,Ca2+-S100B structures are 11.5, 11.5, 11.4, and 11.4 Å, respectively.
a
Calculated using PDB entry 1MHO.
b
H2O ligands to Ca2+ from the pseudo-EF hand.
c
H2O ligands to Ca2+ from the canonical EF hand.