Fig. 3. Superimposition of SIRT2/6 with the complex structures of 5/NAD⁺ (PDB: ; 4RMG) and the SirReal1/AcLys OTC peptide substrate (PDB: ; 4RMI). (A) Colored ribbons; (B) molecular surface; the binding sites of the acetylated substrate, NAD⁺, 6, 5 and SirReal1 are shown in cyan. The carbon atoms of 6, SirReal1, 5, AcLys-OTC peptide and NAD⁺ are colored in black, grey, red, green and yellow, respectively.