Figure 4. The contents and immediate surroundings of the approach to the cyan pocket, and the cyan pocket, labeled for the Av protein (3U7Q).

Atoms O1, O2, O4 of homocitrate are evident in (a), and the blue arrow depicts the general direction of NH₃ movement from the reaction face of FeMo-co. Part (b) shows the relevant residues surrounding the cyan pocket and hydrogen bonding to the chain of water molecules. Hydrogen bonds between water molecules are marked.