Chang Jeong-Ho, Kim Hyun-Chul, Hwang Kwang-Yeon, Lee Joon-Won, Jackson Stephen P, Bell Stephen D, Cho Yunje
National Creative Research Initiative Center for Structural Biology and Department of Life Science, Pohang University of Science and Technology, Hyo-ja dong, San31, Pohang, KyungBook 790-784, South Korea.
J Biol Chem. 2002 Sep 13;277(37):34489-98. doi: 10.1074/jbc.M205460200. Epub 2002 Jun 28.
The NAD-dependent histone/protein deacetylase activity of Sir2 (silent information regulator 2) accounts for its diverse biological roles including gene silencing, DNA damage repair, cell cycle regulation, and life span extension. We provide crystallographic evidence that 2'-O-acetyl ADP-ribose is the reaction product that is formed at the active site of Sir2 from the 2.6-A co-crystal structure of 2'-O-acetyl-ADP-ribose and Sir2 from Archaeoglobus fulgidus. In addition, we show that His-116 and Phe-159 play critical roles in the catalysis and substrate recognition. The conserved Ser-24 and Asp-101 contribute to the stability for NAD binding rather than being directly involved in the catalysis. The crystal structures of wild type and mutant derivatives of Sir2, in conjunction with biochemical analyses of the mutants, provide novel insights into the reaction mechanism of Sir2-mediated deacetylation.
Sir2（沉默信息调节因子2）的NAD依赖型组蛋白/蛋白质脱乙酰酶活性决定了其多种生物学功能，包括基因沉默、DNA损伤修复、细胞周期调控以及寿命延长。我们提供了晶体学证据，表明2'-O-乙酰基ADP-核糖是在Sir2活性位点形成的反应产物，这是基于来自嗜热栖热菌的2'-O-乙酰基ADP-核糖与Sir2的2.6 Å共晶体结构得出的。此外，我们表明His-116和Phe-159在催化和底物识别中起关键作用。保守的Ser-24和Asp-101有助于NAD结合的稳定性，而不是直接参与催化。Sir2野生型和突变衍生物的晶体结构，结合突变体的生化分析，为Sir2介导的脱乙酰化反应机制提供了新的见解。
