α-Haloacetophenone derivatives as photoreversible covalent inhibitors of protein tyrosine phosphatases
α-Haloacetophenone derivatives as photoreversible covalent inhibitors of protein tyrosine phosphatases
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DOI：
10.1021/ja9906756
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发表时间：
1999-06-02
影响因子：
15
通讯作者：
Pei, D
中科院分区：
文献类型：
--
作者：
Arabaci, G;Guo, XC;Pei, D
蛋白质酪氨酸激酶(PTKs)催化蛋白质中磷酸酪氨酸(Py)的形成，而蛋白质酪氨酸磷酸酶(PTPs)则水解Py残基，返回酪氨酸和无机磷，两者相互对立，调节酪氨酸磷酸化水平。到目前为止，已经发现了100多个PTP，据估计，人类基因组中包含多达500个PTP基因。2这些PTPs在生理和病理状态下的确切功能在很大程度上仍不清楚。特定的PTP抑制剂将为研究这些酶的功能以及潜在的治疗药物提供有价值的工具。正是在这个前提下，最近人们对开发PTP抑制剂的兴趣越来越浓厚。3我们报道了R-卤代苯乙酮类化合物是一类新型的有效的共价对苯三酚抑制剂，其抑制作用可以通过350 nm的光解被很方便地逆转。所有来源的对苯三酚都有一个共同的催化结构域∼250个氨基酸，包含唯一的“特征基序”：(I/V)-HC×AG×R(S/T)。2PTP催化的Py水解通过特征基序中保守的半胱氨酸的侧链硫醇对磷酸基团的亲核攻击而进行，形成共价的磷酸半胱氨酸酶中间体，随后被水分子水解(方案1)。4我们设想R-卤代苯乙酮1可以作为Py模拟物与PTP活性中心结合；它的苯环可以像底物的苯环一样与蛋白质发生疏水作用，并且富电子的卤素原子可以模拟带负电荷的磷酸根氧阴离子。以这种方式将1结合到PTP活性部位会将高度易受亲核攻击的R-碳放置在催化半胱氨酸旁边。1与半胱氨酸硫醇发生SN2反应，通过稳定的硫醚键形成共价酶-抑制物加合物，使磷酸酶活性丧失。制备了R-溴和R-氯苯乙酮衍生物(1a-d)，并与典型的磷酸酶PTP1B，6a-Src同源2(SH2)含结构域的磷酸酶进行了比对
The levels of tyrosine phosphorylation are regulated by the opposing actions of protein tyrosine kinases (PTKs), which catalyze the formation of phosphotyrosine (pY) in proteins, and protein tyrosine phosphatases (PTPs), which hydrolyze pY residues to give back tyrosine and inorganic phosphate. More than 100 PTPs have been identified to date, and it is estimated that the human genome contains as many as 500 PTP genes. 2 The precise functions of these PTPs in physiological and pathological states have remained largely unknown. Specific PTP inhibitors would provide valuable tools in studying the functions of these enzymes as well as potential therapeutic agents. It is with this premise that there has been a recently intensified interest in developing PTP inhibitors. 3 Here we report that R-halogenated acetophenones act as a novel class of potent, covalent PTP inhibitors, whose inhibitory effects can be conveniently reversed by photolysis at 350 nm.PTPs of all origins share a common catalytic domain of∼ 250 amino acids, containing the unique “signature motif”,(I/V)-HC× AG×× R (S/T). 2 PTP-catalyzed pY hydrolysis proceeds through a nucleophilic attack on the phosphate group by the sidechain thiol of the conserved cysteine in the signature motif, forming a covalent phosphocysteinyl enzyme intermediate, which is subsequently hydrolyzed by a water molecule (Scheme 1). 4 We envisioned that R-haloacetophenone 1 could bind to the PTP active site as a pY mimetic; its phenyl ring could engage in hydrophobic interactions with the protein as the phenyl ring of a substrate does, and the electron-rich halogen atom could mimic the negatively charged phosphate oxyanions. Binding of 1 to the PTP active site in such a manner would place the R-carbon, which is highly susceptible to nucleophilic attack, next to the catalytic cysteine. An SN2 reaction between 1 and the cysteine thiol would result in the formation of a covalent enzyme-inhibitor adduct through a stable thioether linkage and loss of phosphatase activity. R-Bromo-and R-chloroacetophenone derivatives (1a-d) were prepared5 and assayed against the prototypical phosphatase PTP1B, 6 a Src homology 2 (SH2) domain-containing phosphatase