Lilly Biotechnology Center San Diego, 10300 Campus Point Drive, Suite 200, San Diego, California 92121, USA.
J Med Chem. 2013 Feb 14;56(3):963-9. doi: 10.1021/jm301431y. Epub 2013 Jan 29.
The sirtuin SIRT1 is a NAD(+)-dependent histone deacetylase, a Sir2 family member, and one of seven human sirtuins. Sirtuins are conserved from archaea to mammals and regulate transcription, genome stability, longevity, and metabolism. SIRT1 regulates transcription via deacetylation of transcription factors such as PPARγ, NFκB, and the tumor suppressor protein p53. EX527 (27) is a nanomolar SIRT1 inhibitor and a micromolar SIRT2 inhibitor. To elucidate the mechanism of SIRT inhibition by 27, we determined the 2.5 Å crystal structure of the SIRT1 catalytic domain (residues 241-516) bound to NAD(+) and the 27 analogue compound 35. 35 binds deep in the catalytic cleft, displacing the NAD(+) nicotinamide and forcing the cofactor into an extended conformation. The extended NAD(+) conformation sterically prevents substrate binding. The SIRT1/NAD(+)/35 crystal structure defines a novel mechanism of histone deacetylase inhibition and provides a basis for understanding, and rationally improving, inhibition of this therapeutically important target by drug-like molecules.
SIRT1 是一种依赖 NAD(+)的组蛋白去乙酰化酶，属于 Sir2 家族成员，也是人类 7 种 Sirtuins 之一。Sirtuins 从古细菌到哺乳动物中都有保守性，可调节转录、基因组稳定性、寿命和代谢。SIRT1 通过对转录因子（如 PPARγ、NFκB 和肿瘤抑制蛋白 p53）的去乙酰化来调节转录。EX527（27）是一种纳摩尔级的 SIRT1 抑制剂和微摩尔级的 SIRT2 抑制剂。为了阐明 27 对 SIRT 抑制的机制，我们测定了与 NAD(+)结合的 SIRT1 催化结构域（残基 241-516）的 2.5 Å 晶体结构以及 27 的类似物化合物 35。35 深嵌在催化裂缝中，取代 NAD(+)的烟酰胺并迫使辅因子呈伸展构象。这种伸展的 NAD(+)构象在空间上阻止了底物的结合。SIRT1/NAD(+)/35 的晶体结构定义了组蛋白去乙酰化酶抑制的新机制，并为理解和合理改进药物样分子对这一治疗重要靶点的抑制作用提供了基础。
