The Drosophila carbonyl reductase sniffer is an efficient 4-oxonon-2-enal (4ONE) reductase
The Drosophila carbonyl reductase sniffer is an efficient 4-oxonon-2-enal (4ONE) reductase
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DOI：
10.1016/j.cbi.2010.12.006
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发表时间：
2011-05-30
影响因子：
5.1
通讯作者：
Maser, Edmund
中科院分区：
文献类型：
--
作者：
Martina, Hans-Joerg;Ziemba, Marta;Maser, Edmund
对果蝇（Drosophila melanogaster）的研究表明，这种酶嗅探器可以防止氧化应激诱导的神经变性。与野生型果蝇相比，过度表达嗅探器的突变果蝇在99.5%的氧气气氛中的寿命显着延长。序列分析和数据库检索确定sniffer是短链脱氢酶/还原酶超家族的成员，与人的羰基还原酶I型（CBR 1）有27.4%的同源性。由于CBR 1催化脂质过氧化产物4 HNE和4 ONE的还原，我们测试了嗅探器是否能够通过羰基还原代谢这些脂质衍生的醛。从cDNA文库中扩增sniffer的编码序列，克隆到细菌表达载体中，用镍螯合层析法纯化带His标签的蛋白。我们发现sniffer催化4 ONE的NADPH依赖性羰基还原（K-m = 24 +/- 2 μ M，k（cat）= 500 +/- 10 min（-1），k（cat）/K-m = 350 s（-1）mM（-1）），但不催化4 HNE。HPLC和GC/MS分析表明，嗅探器还原4 ONE的反应产物主要是4 HNE。由于4 HNE，虽然仍然是一个强大的亲电体，是较低的神经毒性和蛋白质反应比4 ONE，嗅探器发挥其神经保护作用的机制之一，在果蝇氧化应激后，可能是酶还原4 ONE。(C)2010爱思唯尔爱尔兰有限公司版权所有。
Studies with the fruit-fly Drosophila melanogaster demonstrated that the enzyme sniffer prevented oxidative stress-induced neurodegeneration. Mutant flies overexpressing sniffer had significantly extended life spans in a 99.5% oxygen atmosphere compared to wild-type flies. However, the molecular mechanism of this protection remained unclear.Sequence analysis and database searches identified sniffer as a member of the short-chain dehydrogenase/reductase superfamily with a 27.4% identity to the human enzyme carbonyl reductase type I (CBR1). As CBR1 catalyzes the reduction of the lipid peroxidation products 4HNE and 4ONE, we tested whether sniffer is able to metabolize these lipid derived aldehydes by carbonyl reduction. To produce recombinant enzyme, the coding sequence of sniffer was amplified from a cDNA-library, cloned into a bacterial expression vector and the His-tagged protein was purified by Ni-chelate chromatography. We found that sniffer catalyzed the NADPH-dependent carbonyl reduction of 4ONE (K-m = 24 +/- 2 mu M, k(cat) = 500 +/- 10 min(-1), k(cat)/K-m = 350 s(-1) mM(-1)) but not that of 4HNE. The reaction product of 4ONE reduction by sniffer was mainly 4HNE as shown by HPLC- and GC/MS analysis. Since 4HNE, though still a potent electrophile, is less neurotoxic and protein reactive than 4ONE, one mechanism by which sniffer exerts its neuroprotective effects in Drosophila after oxidative stress may be enzymatic reduction of 4ONE. (C) 2010 Elsevier Ireland Ltd. All rights reserved.