FIGURE 4.

Phosphocholine bound in the active site of SMPDL3B. A, PC (sticks) in the active site of SMPDL3B, in proximity to loop L9–10 (pink). B, residues that interact with the choline group of PC are shown as sticks (left). Distances between the choline nitrogen atom and the closest protein non-hydrogen atoms are indicated (Å). Residues that form contacts with the phosphate portion of PC, including zinc ions and water, are shown as sticks (right). Interatomic distances are indicated (Å). The electron density F_o − F_c simulated annealing omit map around PC, and the nucleophilic water molecule is contoured at 3σ.