Evolution of the redox function in mammalian apurinic/apyrimidinic endonuclease
Evolution of the redox function in mammalian apurinic/apyrimidinic endonuclease
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DOI：
10.1016/j.mrfmmm.2008.04.008
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发表时间：
2008-08-25
影响因子：
2.3
通讯作者：
Kelley, M. R.
中科院分区：
文献类型：
--
作者：
Georgiadis, M. M.;Luo, M.;Kelley, M. R.
人脱嘌呤/脱嘧啶核酸内切酶（hApe 1）编码两种重要的功能活性：必需碱基切除修复（BER）活性和氧化还原活性，其通过减少转录因子AP-1、NF κ B、HIF-1 α、CREB、p53等来调节许多基因的表达。BER功能与原核生物高度保守（E.大肠杆菌外切核酸酶III）对人（hApe 1）的作用。在这里，我们提供的证据支持氧化还原功能独特的哺乳类人猿。对猿基因序列的进化分析表明，在7个Cys残基中，Cys 93、99、208、296和310在哺乳动物和非哺乳动物脊椎动物猿中都是保守的，而Cys 65是哺乳动物猿所特有的。在斑马鱼猿（zApe）中，被选为与人类最远的脊椎动物序列，与Cys 65相当的残基是Thr 58。在体外EMSA和反式激活测定中测试野生型zApe酶的氧化还原活性，发现其无活性，类似于C65 A hApe 1。然而，在zApe中用Cys取代Thr 58导致氧化还原活性酶，表明在该位置的Cys残基对于氧化还原功能确实是关键的。为了进一步探索氧化还原活性和非活性酶之间的差异，我们已经确定了脊椎动物氧化还原非活性酶，C65 A人类Ape 1酶和zApe酶的晶体结构，分别在1.9和2.3埃。我们的研究结果为氧化还原功能提供了新的见解，并突出了Ape 1在哺乳动物中的功能获得活性，而在非哺乳动物脊椎动物或低等生物中没有发现。(c)2008 Elsevier B. V.保留所有权利。
Human apurinic/apyrimidinic endonuclease (hApe1) encodes two important functional activities: an essential base excision repair (BER) activity and a redox activity that regulates expression of a number of genes through reduction of their transcription factors, AP-1, NF kappa B, HIF-1 alpha, CREB, p53 and others. The BER function is highly conserved from prokaryotes (E. coli exonuclease III) to humans (hApe1). Here, we provide evidence supporting a redox function unique to mammalian Apes. An evolutionary analysis of Ape sequences reveals that, of the 7 Cys residues, Cys 93, 99, 208, 296, and 310 are conserved in both mammalian and non-mammalian vertebrate Apes, while Cys 65 is unique to mammalian Apes. In the zebrafish Ape (zApe), selected as the vertebrate sequence most distant from human, the residue equivalent to Cys 65 is Thr 58. The wild-type zApe enzyme was tested for redox activity in both in vitro EMSA and transactivation assays and found to be inactive, similar to C65A hApe1. Substitution of Thr 58 with Cys in zApe, however, resulted in a redox active enzyme, suggesting that a Cys residue in this position is indeed critical for redox function. In order to further probe differences between redox active and inactive enzymes, we have determined the crystal structures of vertebrate redox inactive enzymes, the C65A human Ape1 enzyme and the zApe enzyme at 1.9 and 2.3 angstrom, respectively. Our results provide new insights on the redox function and highlight a dramatic gain-of-function activity for Ape1 in mammals not found in non-mammalian vertebrates or lower organisms. (c) 2008 Elsevier B.V. All rights reserved.