Functional analysis of the p300 acetyltransferase domain:: the PHD finger of p300 but not of CBP is dispensable for enzymatic activity
Functional analysis of the p300 acetyltransferase domain:: the PHD finger of p300 but not of CBP is dispensable for enzymatic activity
复制标题
DOI：
10.1093/nar/29.21.4462
复制
发表时间：
2001-11-01
影响因子：
14.9
通讯作者：
Eckner, R
中科院分区：
文献类型：
--
作者：
Bordoli, L;Hüsser, S;Eckner, R
核小体组蛋白乙酰化是真核基因表达激活过程中的一个重要调控步骤。在已知的乙酰转移酶（AT）家族中，GNAT超家族的结构-功能关系是最好理解的。相比之下，较少的信息是关于p300/CBP AT功能的机制和监管方面。在本文中，我们调查的结构和序列的要求更详细的p300/CBP酶活性。出乎意料的是，我们发现p300的PHD指，而不是CBP，是AT活性的标志。为了确定参与底物或乙酰辅酶A（乙酰辅酶A）识别的残基，我们在动物和植物p300/CBP蛋白之间高度保守的片段中引入了19个不同的氨基酸取代。通过与组蛋白、p53肽或AT结构域本身进行乙酰化反应，我们定义了组蛋白和p53底物募集所需的几个残基，但不用于乙酰辅酶A结合。最后，我们发现，相同的突变在p300和CBP AT域损害AT活性不同。后一结果结合发现的差异要求的PHD手指提供的证据，p300和CBP之间的结构差异，可能在一定程度上是以前报道的两种蛋白质的功能专业化。
Acetylation of nucleosomal histones is a major regulatory step during activation of eukaryotic gene expression. Among the known acetyltransferase (AT) families, the structure-function relationship of the GNAT superfamily is the most well understood. In contrast, less information is available regarding mechanistic and regulatory aspects of p300/CBP AT function. In this paper, we investigate in closer detail the structure and sequence requirements for p300/CBP enzymatic activity. Unexpectedly, we find that the PHD finger of p300, but not of CBP, is dispensable for AT activity. In order to identify residues involved in substrate or acetyl-coenzyme A (acetyl-CoA) recognition, we have introduced 19 different amino acid substitutions in segments that are highly conserved between animal and plant p300/CBP proteins. By performing acetylation reactions with histones, a p53 peptide or the AT domain itself, we define several residues required for histone and p53 substrate recruitment but not for acetyl-CoA binding. Finally, we show that identical mutations in the p300 and CBP AT domain impair AT activity differently. This latter result combined with the finding of a differential requirement for the PHD finger provides evidence for structural differences between p300 and CBP that may in part underlie a previously reported functional specialization of the two proteins.