Figure 2

Substrate-binding pocket of mIDH2. (a) Structural overview of wild-type mIDH2. Wild-type mIDH2 is a homodimer with two subunits, one colored green and one slate blue. An isocitrate molecule and a Mg²⁺ ion were bound in each subunit and are represented by the magenta stick and magenta sphere, respectively. (b) Conserved domains of mIDH2. The large domain (residues 40–152 and 327–452), the small domain (residues 153–180 and 224–326) and the clasp domain (residues 181–223) are shown in yellow, green and blue, respectively. (c) Residues involved in isocitrate and Mg²⁺ binding (subunit A). Isocitrate is shown as a green stick, and Mg²⁺ is shown as a green sphere. Amino acid residues are represented by white sticks. Blue and red indicate nitrogen and oxygen atoms, respectively. Superscript capital letters for amino residues represent which subunit they are from. Hydrogen bonds are represented using dashed lines. (d) The electrostatic surface of wild-type mIDH2. The surface view of the overall structure (left panel) and a close-up view of the substrate-binding pocket (right panel) are shown. The electrostatic potential of the surface is colored in a range from −12 kTe⁻¹ (red) to + 12 kTe⁻¹ (blue). Isocitrate and Mg²⁺ are shown in green.