Center for Chemical Biology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
College of Pharmacy, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
Molecules. 2022 Apr 22;27(9):2714. doi: 10.3390/molecules27092714.
SIRT1, an NAD-dependent deacetylase, catalyzes the deacetylation of proteins coupled with the breakdown of NAD into nicotinamide and 2'-O-acetyl-ADP-ribose (OAADPr). Selective SIRT1 activators have potential clinical applications in atherosclerosis, acute renal injury, and Alzheimer's disease. Here, we found that the activity of the potent SIRT1 activator CWR is independent of the acetylated substrate. It adopts a novel mechanism to promote SIRT1 activity by covalently bonding to the anomeric C1' carbon of the ribose ring in OAADPr. In addition, CWR is highly selective for SIRT1, with no effect on SIRT2, SIRT3, SIRT5, or SIRT6. The longer distance between the anomeric C1' carbon of the ribose ring in OAADPr and Arg274 of SIRT1 (a conserved residue among sirtuins) than that between the anomeric C1' carbon in OAADPr and the Arg of SIRT2, SIRT3, SIRT5, and SIRT6, should be responsible for the high selectivity of CWR for SIRT1. This was confirmed by site-directed mutagenesis of SIRT3. Consistent with the in vitro assays, the activator also reduced the acetylation levels of p53 in a concentration-dependent manner via SIRT1 in cells. Our study provides a new perspective for designing SIRT1 activators that does not rely on the chemical moiety immediately C-terminal to the acetyl-lysine of the substrate.
SIRT1 是一种 NAD 依赖性去乙酰化酶，可催化与 NAD 分解为烟酰胺和 2'-O-乙酰-ADP-核糖（OAADPr）偶联的蛋白质去乙酰化。选择性 SIRT1 激活剂在动脉粥样硬化、急性肾损伤和阿尔茨海默病等疾病中有潜在的临床应用。在这里，我们发现强效 SIRT1 激活剂 CWR 的活性不依赖于乙酰化底物。它通过与 OAADPr 中核糖环的端基 C1'碳原子共价结合，采用一种新的机制来促进 SIRT1 活性。此外，CWR 对 SIRT1 具有高度选择性，对 SIRT2、SIRT3、SIRT5 和 SIRT6 没有影响。OAADPr 中核糖环的端基 C1'碳原子与 SIRT1 的 Arg274（在所有 sirtuins 中保守的残基）之间的距离比 OAADPr 中端基 C1'碳原子与 SIRT2、SIRT3、SIRT5 和 SIRT6 的 Arg 之间的距离要长，这应该是 CWR 对 SIRT1 具有高选择性的原因。这通过 SIRT3 的定点突变得到了证实。与体外测定一致，该激活剂还通过 SIRT1 在细胞中浓度依赖性地降低 p53 的乙酰化水平。我们的研究为设计不依赖于底物乙酰化赖氨酸 C 端化学基团的 SIRT1 激活剂提供了新的视角。
