组蛋白乙酰化在调节细胞进程中起着重要的作用。酿酒酵母Rtt109是一类重要的组蛋白乙酰转移酶（HATs），它能通过直接对新合成组蛋白H3赖氨酸56进行乙酰化，来促进基因组稳定（H3-K56），但其中的机制目前尚属未知。
在10月8日的《结构》（Structure）中，Lin和Yuan等人报道了Rtt109的晶体结构为2.2 Å；而Rtt109/Acetyl-CoA复合体为1.9 Å的研究数据。Rtt109结构为三层混合的α/ β模块组成的中央模块，其核心区域的结构与GCN5 HAT和P300/CBP HAT的结构域相似。通过结构和生化分析，研究人员发现了Rtt109蛋白的催化活性部位；确定了Asp288为去质子残基；Lys290为自动乙酰化残基。
Lin等人还在进一步的研究中发现了独特的蛋白H3-K56锚定袋和潜在的H3αN制动槽，从而揭开了Rtt109蛋白通过 H3-K56完成乙酰化的分子机制。（生物谷Bioon.com）
生物谷推荐原始出处：
Structure，Volume 16, Issue 10, 1503-1510, 8 October 2008，Chengqi Lin and Y. Adam Yuan
Structural Insights into Histone H3 Lysine 56 Acetylation by Rtt109
Chengqi Lin1andY. Adam Yuan1,,
1 Genome and Structural Biology Program, Temasek Life Sciences Laboratory and Department of Biological Sciences, National University of Singapore, 1 Research Link, Singapore 117604, Singapore
SUMMARY
Histone acetylation plays important roles for the regulation of many fundamental cellular processes. Saccharomyces cerevisiae Rtt109 is an important class of histone acetyltransferases (HATs), whichpromote genome stability by directly acetylating newly synthesized histone H3 lysine 56 (H3-K56) through an unknown mechanism. Here, we report the crystal structures of Rtt109 at 2.2 ? and Rtt109/Acetyl-CoA binary complex at 1.9 ?. The structure displaysa vise-like topology with mixed three-layered / module forming the central module, whose core region resembles the structure of GCN5 HAT domain and P300/CBP HAT domain. Using structural and biochemical analyses, we have discovered the catalytic active site and have identified Asp288 as the deprotonation residue and Lys290 as the autoacetylation residue. We have further proposed the unique H3-K56 anchoring pocket and the potential H3N binding groove. Our work has provided structural insights tounderstand the acetylation mechanism of H3-K56 by Rtt109.
