Figure 6. . Sirtuin activators.

(A) Structures and enzymatic activities of SIRT1a 23–24. (B) Structure of STAC 24h and x-ray crystal structure of mini-hSIRT1 in complex with 24h (PDB ID: 4ZZH) [194] with details showing the hydrogen bond with N226 and the hydrophobic interactions with surrounding residues. Mini-hSIRT1 is colored in green with selected residues shown in white sticks, 24h is represented as yellow sticks, the hydrogen bond is represented as a magenta dotted line, Zn²⁺ is represented as a dark sphere. (C–D) Structures and enzymatic activities of DHP-based SIRTa 25a–d (C) and SIRT6a 26–28 (D).