Citrate Synthase is a homodimer where the termini of each subunit wrap around the other to form the enzyme

The protein is mainly alpha helical, with each domain consisting of 20 helices and 2 anti-parallel beta sheets.

Much of the surface consists of polar residues, while the interior is mainly hydrophobic.

Since Citrate Synthase catalyzes enol formation and condensation, acidic and basic residues are found in high concentration near the subunit interface ( active site).

This particular crystal structure contains bound citrate and Co-enzyme A, the end products of the reaction. In the first few steps of the reaction, there are many acid/base proton transfers and water is excluded from the active site. When the intermediate citronyl-CoA is formed, a conformational change is induced, allowing water to enter the active site and hydrolyze the sulfur-citronyl bond.