NADP+-dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis
NADP+-dependent farnesol dehydrogenase, a corpora allata enzyme involved in juvenile hormone synthesis
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DOI：
10.1073/pnas.0909938106
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发表时间：
2009-12-15
影响因子：
11.1
通讯作者：
Noriega, Fernando G.
中科院分区：
文献类型：
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作者：
Mayoral, Jaime G.;Nouzova, Marcela;Noriega, Fernando G.
保幼激素（juvenile hormone，JH）的合成是控制害虫和疾病媒介的一个有吸引力的目标，但是合成JH的腺体咽侧体（corpora allata，CA）的微小尺寸使得难以通过经典的生物化学方法鉴定重要的生物合成酶。在这里，我们报告的鉴定和表征的昆虫法呢醇脱氢酶（AaSDR-1），氧化法呢醇成法呢醛，前体的JH，在CA。AaSDR-1作为EST在埃及伊蚊（Aedes aegypti）的咽侧体-心侧体文库中分离。该245个氨基酸的蛋白质呈现用于核苷酸结合的典型短链脱氢酶（SDR）Rossmann折叠基序。该特征与其他保守序列基序一起将AaSDR-1置于“经典”NADP（+）依赖性cP 2 SDR亚家族中。该基因是一组高度保守的旁系同源物的一部分，这些旁系同源物在蚊子基因组中聚集在一起;在其他昆虫物种中也发现了类似的直系同源物簇。AaSDR-1作为同二聚体并有效地氧化C-10至C-15类异戊二烯和脂肪醇，显示出对法呢醇转化为法呢醛的最高亲和力。法呢醇脱氢酶活性未检测到CA的新出现的蚊子，但显着的活性检测24小时后。真实的时间PCR实验显示，AaSDR-1 mRNA水平在新出现的雌性的失活CA中非常低，但在24小时后的JH合成高峰期间增加>30倍。这些结果表明，氧化法呢醇可能是一个限速步骤，在JH III合成成蚊。
The synthesis of juvenile hormone (JH) is an attractive target for control of insect pests and vectors of disease, but the minute size of the corpora allata (CA), the glands that synthesize JH, has made it difficult to identify important biosynthetic enzymes by classical biochemical approaches. Here, we report identification and characterization of an insect farnesol dehydrogenase (AaSDR-1) that oxidizes farnesol into farnesal, a precursor of JH, in the CA. AaSDR-1 was isolated as an EST in a library of the corpora allata-corpora cardiaca of the mosquito Aedes aegypti. The 245-amino acid protein presents the typical short-chain dehydrogenase (SDR) Rossmann-fold motif for nucleotide binding. This feature, together with other conserved sequence motifs, place AaSDR-1 into the "classical'' NADP(+)-dependent cP2 SDR subfamily. The gene is part of a group of highly conserved paralogs that cluster together in the mosquito genome; similar clusters of orthologs were found in other insect species. AaSDR-1 acts as a homodimer and efficiently oxidizes C-10 to C-15 isoprenoid and aliphatic alcohols, showing the highest affinity for the conversion of farnesol into farnesal. Farnesol dehydrogenase activity was not detected in the CA of newly emerged mosquitoes but significant activity was detected 24 h later. Real time PCR experiments revealed that AaSDR-1 mRNA levels were very low in the inactive CA of the newly emerged female, but increased >30-fold 24 h later during the peak of JH synthesis. These results suggest that oxidation of farnesol might be a rate-limiting step in JH III synthesis in adult mosquitoes.