Figure 5

Magnesium-ion-binding site in c5321. A. Mg²⁺ coordination by residues H99 of SLR3, E136 of SLR4 and D138 of the intra-repeat loop. Alanine at repeat position 10 (A133) is indicated to highlight the lack of VdW contacts in the corresponding area. B. Electron density map (σ_A-weighted 2Fo - Fc contoured at 2σ) at the metal-ion-binding site, including the three water molecules that complete the coordination.