Figure 4
Binding of PEP in the active site of SeEN. The PEP molecule is shown in the two conformations found in chains A (green) and B (blue) of PDB entry 5j04. The water molecule `w' is 3.5 Å from C3 of the PEP molecule (red dotted line) and is hydrogen-bonded to His367 and Glu168. Compare with Fig. 2. Presumably, during the dehydration of 2PGA or the hydration of PEP (bottom), a water molecule is exchanged from the Glu168 side, whereas proton extraction occurs from the opposite side, with Lys339 acting as a strong base. |