Reconstitution of Nucleosome Demethylation and Catalytic Properties of a Jumonji Histone Demethylase
Reconstitution of Nucleosome Demethylation and Catalytic Properties of a Jumonji Histone Demethylase
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DOI：
10.1016/j.chembiol.2013.03.008
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发表时间：
2013-04-18
影响因子：
--
通讯作者：
Fujimori, Danica Galonic
中科院分区：
文献类型：
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作者：
Shiau, Carrie;Trnka, Michael J.;Fujimori, Danica Galonic
Jumonji组蛋白去甲基化酶催化核小体内组蛋白赖氨酸残基甲基标记的去除。在这里，我们发现去甲基化酶JMJD2A （cJMJD2A）的催化结构域利用分配机制去除组蛋白H3赖氨酸9三甲基标记。通过开发一种评估同质、位点特异性甲基化核小体去甲基化的方法，我们确定cJMJD2A核小体去甲基化的动力学参数与肽底物的动力学参数相当。这些发现表明，去甲基化酶的其他结构域或其蛋白质伙伴可能有助于体内核小体识别，并以此方式进一步调节去甲基化活性和过程。在我们的工作中开发的核小体去甲基化的定量分析为未来复杂染色质底物和全长去甲基化酶的工作提供了一个平台。
Jumonji histone demethylases catalyze removal of methyl marks from lysine residues in histone proteins within nucleosomes. Here, we show that the catalytic domain of demethylase JMJD2A (cJMJD2A) utilizes a distributive mechanism to remove the histone H3 lysine 9 trimethyl mark. By developing a method to assess demethylation of homogeneous, site-specifically methylated nucleosomes, we determined that the kinetic parameters for demethylation of nucleosomes by cJMJD2A are comparable to those of peptide substrates. These findings imply that other domains of the demethylase or its protein partners may contribute to nucleosome recognition in vivo and, in this way, may further regulate demethylation activity and processivity. The quantitative assays of nucleosome demethylation developed in our work provide a platform for future work with complex chromatin substrates and full-length demethylases.