Figure 2: Structure of Mini-hSIRT1/1 complex.

(a) Structure of Mini-hSIRT1/1 complex shown in ribbon diagram. The α-helices and β-strands in the catalytic domain are shown in cyan and orange, respectively. The α-helices in the N-terminal SBD are shown in blue. The β-strands in the C-terminal CTR are shown in red. All the loops are shown in light gray. The STAC 1 is shown in green, red and blue for carbon, oxygen and nitrogen atoms. The zinc ion is shown as a gray sphere. (b) hSIRT1-binding site of 1 with interacting residues shown in stick representation. Hydrogen bonds are shown as yellow dotted lines. (c) Stereo view of the electrostatic surface potential of the N-terminal SBD and electron density map of STAC 1. The electrostatic potential is contoured at the 5 kT/e level, with red denoting negative potential and blue denoting positive potential. The 2Fo-Fc omit map of 1 is contoured at 1.0 σ level. (d) Crystallographic dimer of Mini-hSIRT1/1 complex. The protein ribbon is rainbow-colored from blue at the N-terminus to red at the C-terminus.