Structural Insight into the Interactions between Structurally Similar Inhibitors and SIRT6.

Sirtuin 6 (SIRT6) is an NAD+-dependent deacetylase with a significant role in 20% of all cancers, such as colon cancers and rectal adenocarcinoma. However, there is currently no effective drug for cancers related to SIRT6. To explore potential inhibitors of SIRT6, it is essential to reveal details of the interaction mechanisms between inhibitors and SIRT6 at the atomic level. The nature of small molecules from herbs have many advantages as inhibitors. Based on the conformational characteristics of the inhibitor Compound 9 (Asinex ID: BAS13555470), we explored the natural molecule Scutellarin, one compound of Huang Qin, which is an effective herb for curing cancer that has been described in the Traditional Chinese Medicine (TCMS) library. We investigated the interactions between SIRT6 and the inhibitors using molecular dynamics (MD) simulations. We illustrated that the structurally similar inhibitors have a similar binding mode to SIRT6 with residues-Leu9, Phe64, Val115, His133 and Trp188. Hydrophobic and π-stacking interactions play important roles in the interactions between SIRT6 and inhibitors. In summary, our results reveal the interactive mechanism of SIRT6 and the inhibitors and we also provide Scutellarin as a new potential inhibitor of SIRT6. Our study provides a new potential way to explore potential inhibitors from TCMS.