Orphan Macrodomain Protein (Human C6orf130) Is an O-Acyl-ADP-ribose Deacylase
Orphan Macrodomain Protein (Human C6orf130) Is an O-Acyl-ADP-ribose Deacylase
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DOI：
10.1074/jbc.m111.276238
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
F. Peterson;Dawei Chen;B. Lytle;M. Rossi;Ivan Ahel;J. Denu;B. Volkman
中科院分区：
文献类型：
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作者：
F. Peterson;Dawei Chen;B. Lytle;M. Rossi;Ivan Ahel;J. Denu;B. Volkman
背景：sirtuins使蛋白质去酰化产生o -酰基adp核糖分子，参与细胞信号传导和代谢。结果：人类孤儿大结构域蛋白的结构和功能分析揭示了一个共同的核心结构和水解o -酰基- adp核糖的能力。结论：不同的大结构域能够水解o -酰基- adp核糖，但使用不同的催化氨基酸。意义：含有大结构域的蛋白为sirtuin依赖性去酰化提供了生化和生物学联系。赖氨酸酰化对蛋白质/组蛋白的翻译后修饰对修饰蛋白的生理功能有深远的影响。NAD+依赖性sirtuin反应的去酰化产生o -酰基adp核糖，该核糖被认为是调节细胞过程的信号分子。据报道，含有大结构域的蛋白可以结合NAD+衍生的代谢物。在这里，我们描述了一个孤儿大结构域蛋白，人C6orf130的结构和功能。这个独特的17 kda蛋白是一个独立的大结构域蛋白，在系统发育树中占据一个独特的分支。我们证明了C6orf130催化o -乙酰- adp核糖、o -丙酰- adp核糖和o -丁基- adp核糖的高效去酰化，分别生成adp核糖（ADPr）和醋酸盐、丙酸盐和丁酸盐。利用核磁共振波谱技术，对C6orf130在ADPr存在和不存在情况下的结构进行了解析。结构呈典型折叠，具有深配体（ADPr）结合间隙。apo-C6orf130和ADPr- c6orf130复合物的结构比较揭示了覆盖结合ADPr的β5-α4环的波动，这表明β5-α4环具有隔离底物的功能，并具有灵活性以容纳替代底物。ADPr-C6orf130复合体鉴定了参与底物结合的氨基酸残基，并提示了在催化中起作用的残基。位点特异性突变和稳态动力学分析揭示了两个关键的催化残基，Ser-35和Asp-125。我们提出了C6orf130催化o -酰基- adp核糖去酰化的机制，并讨论了在赖氨酸残基可逆蛋白酰化的背景下的生物学意义。
Background: Protein deacylation by sirtuins yields O-acyl-ADP-ribose molecules, which are implicated in cell signaling and metabolism. Results: Structural and functional analysis of a human orphan macrodomain protein reveals a common core structure and ability to hydrolyze O-acyl-ADP-ribose. Conclusion: Diverse macrodomains are capable of hydrolyzing O-acyl-ADP-ribose but utilize a different set of catalytic amino acids. Significance: Macrodomain-containing proteins provide a biochemical and biological link to sirtuin-dependent deacylation. Post-translational modification of proteins/histones by lysine acylation has profound effects on the physiological function of modified proteins. Deacylation by NAD+-dependent sirtuin reactions yields as a product O-acyl-ADP-ribose, which has been implicated as a signaling molecule in modulating cellular processes. Macrodomain-containing proteins are reported to bind NAD+-derived metabolites. Here, we describe the structure and function of an orphan macrodomain protein, human C6orf130. This unique 17-kDa protein is a stand-alone macrodomain protein that occupies a distinct branch in the phylogenic tree. We demonstrate that C6orf130 catalyzes the efficient deacylation of O-acetyl-ADP-ribose, O-propionyl-ADP-ribose, and O-butyryl-ADP-ribose to produce ADP-ribose (ADPr) and acetate, propionate, and butyrate, respectively. Using NMR spectroscopy, we solved the structure of C6orf130 in the presence and absence of ADPr. The structures showed a canonical fold with a deep ligand (ADPr)-binding cleft. Structural comparisons of apo-C6orf130 and the ADPr-C6orf130 complex revealed fluctuations of the β5-α4 loop that covers the bound ADPr, suggesting that the β5-α4 loop functions as a gate to sequester substrate and offer flexibility to accommodate alternative substrates. The ADPr-C6orf130 complex identified amino acid residues involved in substrate binding and suggested residues that function in catalysis. Site-specific mutagenesis and steady-state kinetic analyses revealed two critical catalytic residues, Ser-35 and Asp-125. We propose a catalytic mechanism for deacylation of O-acyl-ADP-ribose by C6orf130 and discuss the biological implications in the context of reversible protein acylation at lysine residues.