Lin Y, Fletcher C M, Zhou J, Allis C D, Wagner G
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Nature. 1999 Jul 1;400(6739):86-9. doi: 10.1038/21922.
Gene transcription requires the release of inactive DNA from its packaging of histone proteins. Following the discovery of the first transcription-associated histone acetyltransferase, tetrahymena GCN5, it was shown that yeast GCN5 is recruited to the promoter and causes hyper-acetylation of histones and transcriptional activation of target genes, establishing a direct connection between histone acetylation and transcriptional activation. Many other important transcription regulators have been found to have histone acetyltransferase activity, including TAFII230/250, p300/CBP and its associated factor PCAF. Here we present the solution structure of the catalytic domain of tGCN5 (residues 47-210) in complex with coenzyme A. The structure contains two domains; the amino-terminal domain is similar to those of other GCN5-related N-acetyltransferases but the carboxy-terminal domain is not. Coenzyme A binds in a deep hydrophobic pocket between the two domains. Chemical shift changes upon titration with histone H3 peptides indicate a binding site at the domain boundary opposite to the coenzyme A site. The structural data indicate a single-step acetyl-transfer reaction mechanism catalysed by a hydrogen bond to the backbone amide group of leucine 126 and the side-chain carboxyl group of a conserved acidic residue.
基因转录需要将无活性的DNA从其组蛋白包装中释放出来。在发现第一个与转录相关的组蛋白乙酰转移酶——四膜虫GCN5之后，研究表明酵母GCN5被招募到启动子上，导致组蛋白的超乙酰化和靶基因的转录激活，从而在组蛋白乙酰化和转录激活之间建立了直接联系。已发现许多其他重要的转录调节因子具有组蛋白乙酰转移酶活性，包括TAFII230/250、p300/CBP及其相关因子PCAF。本文展示了与辅酶A结合的tGCN5催化结构域（第47 - 210位氨基酸残基）的溶液结构。该结构包含两个结构域；氨基末端结构域与其他GCN5相关的N - 乙酰转移酶的结构域相似，但羧基末端结构域则不同。辅酶A结合在两个结构域之间的一个深疏水口袋中。用组蛋白H3肽滴定后的化学位移变化表明在与辅酶A位点相对的结构域边界处存在一个结合位点。结构数据表明，由与亮氨酸126的主链酰胺基团和一个保守酸性残基的侧链羧基形成的氢键催化单步乙酰转移反应机制。
