Catalytic activity and inhibition of human histone deacetylase 8 is dependent on the identity of the active site metal ion
Catalytic activity and inhibition of human histone deacetylase 8 is dependent on the identity of the active site metal ion
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DOI：
10.1021/bi060212u
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发表时间：
2006-05-16
期刊：
影响因子：
2.9
通讯作者：
Fierke, Carol A.
中科院分区：
文献类型：
--
作者：
Gantt, Stephanie L.;Gattis, Samuel G.;Fierke, Carol A.
组蛋白脱乙酰酶通过催化ε-乙酰基-赖氨酸残基的水解在调节转录和其他细胞过程中起关键作用。因此，组蛋白脱乙酰酶抑制剂是治疗癌症的潜在靶点。这些酶的一个子集先前已被证明需要二价金属离子进行催化。在这里，我们证明了组蛋白脱乙酰酶8（HDAC 8）与一定数量的二价金属离子以1：1的化学计量比具有以下比活性顺序的催化活性：Co（II）> Fe（II）> Zn（II）> Ni（II）。催化金属离子的特性影响HDAC抑制剂辛二酰苯胺异羟肟酸（SAHA）的亲和力和米氏常数，其中Fe（II）-和Co（II）-HDAC 8的K-M值比Zn（II）HDAC 8的K-M值低5倍以上。这些数据表明，Fe（II），而不是Zn（II），可能是体内催化金属。为了进一步支持这一假设，从E.在透析前，大肠杆菌中的铁含量是锌的8倍，并且细胞裂解物中的HDAC 8活性是氧敏感的。HDAC 8的体内金属离子的鉴定对于理解HDAC 8的生物学功能和调节以及开发这类酶的改进抑制剂是必不可少的。
Histone deacetylases play a key role in regulating transcription and other cellular processes by catalyzing the hydrolysis of epsilon-acetyl-lysine residues. For this reason, inhibitors of histone deacetylases are potential targets for the treatment of cancer. A subset of these enzymes has previously been shown to require divalent metal ions for catalysis. Here we demonstrate that histone deacetylase 8 (HDAC8) is catalytically active with a number of divalent metal ions in a 1:1 stoichiometry with the following order of specific activity: Co(II) > Fe(II) > Zn(II) > Ni(II). The identity of the catalytic metal ion influences both the affinity of the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) and the Michaelis constant, with Fe(II)- and Co( II)- HDAC8 having K-M values that are over 5-fold lower than that of Zn( II)HDAC8. These data suggest that Fe( II), rather than Zn( II), may be the in vivo catalytic metal. In further support of this hypothesis, recombinant HDAC8 purified from E. coli contains 8-fold more iron than zinc before dialysis, and the HDAC8 activity in cell lysates is oxygen-sensitive. Identification of the in vivo metal ion of HDAC8 is essential for understanding the biological function and regulation of HDAC8 and for the development of improved inhibitors of this class of enzymes.