Enzymatic properties of ALDH1L2, a mitochondrial 10-formyltetrahydrofolate dehydrogenase.
Enzymatic properties of ALDH1L2, a mitochondrial 10-formyltetrahydrofolate dehydrogenase.
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DOI：
10.1016/j.cbi.2011.01.008
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发表时间：
2011-05-30
影响因子：
5.1
通讯作者：
Krupenko, Sergey A.
中科院分区：
文献类型：
--
作者：
Strickland, Kyle C.;Krupenko, Natalia I.;Dubard, Marianne E.;Hu, Calvin J.;Tsybovsky, Yaroslav;Krupenko, Sergey A.
关键词：
10-甲酰四氢叶酸脱氢酶（10-Formyltetrahydrofolate dehydrogenase， FDH, ALDH1L1）是一种丰富的叶酸代谢细胞质酶，与醛脱氢酶（ALDH）家族酶具有显著的序列相似性。该酶以NADP+依赖的方式将10-甲酰基四氢叶酸（10-fTHF）转化为四氢叶酸和二氧化碳。该反应的机理包括三个连续的步骤，最后发生在aldh同源结构域。我们最近发现了FDH的线粒体异构体（mtFDH），它是一个单独的基因ALDH1L2的产物。其与细胞质内FDH的整体同源性约为74%，ALDH结构域之间的同源性高达79%。在本研究中，人mtFDH在大肠杆菌中表达，纯化到均匀性，并进行了表征。虽然重组酶能够催化10-fTHF水解酶反应，但它没有产生可检测水平的ALDH活性。尽管缺乏典型的ALDH催化作用，但在辅酶a存在的情况下，重组4 ' -磷酸甲肽转移酶（PPT）再激活mtFDH后，mtFDH能够进行典型的10-fTHF脱氢酶反应。利用定点诱变，确定PPT特异性修饰mtFDH的Ser375位点。mtFDH的c端结构域（残基413-923）也在大肠杆菌中表达并进行了表征。这个结构域被发现以四聚体的形式存在，并催化酯酶反应，这是其他ALDH酶的典型反应。综上所述，我们的研究表明ALDH1L2具有与其细胞质对应物相似的酶特性，尽管目前无法催化与短链醛底物的ALDH反应仍然是一个未解决的问题。
10-Formyltetrahydrofolate dehydrogenase (FDH, ALDH1L1), an abundant cytosolic enzyme of folate metabolism, shares significant sequence similarity with enzymes of the aldehyde dehydrogenase (ALDH) family. The enzyme converts 10-formyltetrahydrofolate (10-fTHF) to tetrahydrofolate and CO2 in an NADP+-dependent manner. The mechanism of this reaction includes three consecutive steps with the final occurring in an ALDH-homologous domain. We have recently identified a mitochondrial isoform of FDH (mtFDH), which is the product of a separate gene, ALDH1L2. Its overall identity to cytosolic FDH is about 74%, and the identity between the ALDH domains rises up to 79%. In the present study, human mtFDH was expressed in E. coli, purified to homogeneity, and characterized. While the recombinant enzyme was capable of catalyzing the 10-fTHF hydrolase reaction, it did not produce detectable levels of ALDH activity. Despite the lack of typical ALDH catalysis, mtFDH was able to perform the characteristic 10-fTHF dehydrogenase reaction after reactivation by recombinant 4′-phosphopantetheinyl transferase (PPT) in the presence of coenzyme A. Using site-directed mutagenesis, it was determined that PPT modifies mtFDH specifically at Ser375. The C-terminal domain of mtFDH (residues 413-923) was also expressed in E. coli and characterized. This domain was found to exist as a tetramer and to catalyze an esterase reaction that is typical of other ALDH enzymes. Taken together, our studies suggest that ALDH1L2 has enzymatic properties similar to its cytosolic counterpart, although the inability to catalyze the ALDH reaction with short-chain aldehyde substrates remains an unresolved issue at present.
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影响因子：
4.8
作者：
Chumanevich, AA;Krupenko, SA;Davies, C
通讯作者：
Davies, C
影响因子：
3.9
作者：
COOK, RJ;WAGNER, C
通讯作者：
WAGNER, C
影响因子：
2.9
作者：
GARCIAMARTINEZ, LF;APPLING, DR
通讯作者：
APPLING, DR
影响因子：
5.1
作者：
Krupenko, Sergey A.
通讯作者：
Krupenko, Sergey A.
DOI：
10.1016/0006-291x(69)90633-0
发表时间：
1969-01-01
影响因子：
3.1
作者：
GALPER, JB;DARNELL, JE
通讯作者：
DARNELL, JE