Cloning and characterization of a eukaryotic pantothenate kinase gene (panK) from Aspergillus nidulans
Cloning and characterization of a eukaryotic pantothenate kinase gene (panK) from Aspergillus nidulans
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DOI：
10.1074/jbc.274.4.2014
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发表时间：
1999-01-22
影响因子：
4.8
通讯作者：
Jackowski, S
中科院分区：
文献类型：
--
作者：
Calder, RB;Williams, RSB;Jackowski, S
泛酸激酶（PanK）是辅酶A生物合成途径中的关键调控酶，大肠杆菌PanK基因（coaA）已被克隆并进行了生物化学表征，在其他原核生物中也存在高度相关的基因。我们从真核真菌构巢曲霉中克隆了一个PanK基因的cDNA克隆。coliPanK突变体。cDNA克隆允许基因组克隆的分离和A. nidulans基因命名为panK。panK基因位于染色体上（连锁群III），被三个小内含子中断，组成型表达。构巢曲霉PanK（aPanK）的氨基酸序列预测亚基大小为46.9 kDa，与其细菌对应物几乎没有相似之处，而在酿酒酵母的基因组中检测到高度相关的蛋白质。与E. coli PanK（bPanK）中，aPanK的活性受CoA的调节，但受硫酯的调节程度较低，乙酰辅酶A对aPanK活性有选择性的抑制作用，乙酰辅酶A对aPanK的抑制作用与ATP具有竞争性。因此，真核PanK具有独特的一级结构和独特的调控特性，清楚地将其与原核对应物区分开来。
Pantothenate kinase (PanK) is the key regulatory enzyme in the CoA biosynthetic pathway, The PanK gene from Escherichia coli (coaA) has been previously cloned and the enzyme biochemically characterized; highly related genes exist in other prokaryotes. We isolated a PanK cDNA clone from the eukaryotic fungus Aspergillus nidulans by functional complementation of a temperature-sensitive E. coli PanK mutant. The cDNA clone allowed the isolation of the genomic clone and the characterization of the A. nidulans gene designated panK. The panK gene is located on chromosome (linkage group III), is interrupted by three small introns, and is expressed constitutively. The amino acid sequence of A, nidulans PanK (aPanK) predicted a subunit size of 46.9 kDa and bore little resemblance to its bacterial counterpart, whereas a highly related protein was detected in the genome of Saccharomyces cerevisiae. In contrast to E. coli PanK (bPanK), which is regulated by CoA and to a lesser extent by its thioesters, aPanK activity was selectively and potently inhibited by acetyl-CoA, Acetyl-CoA inhibition of aPanK was competitive with respect to ATP. Thus, the eukaryotic PanK has a distinct primary structure and unique regulatory properties that clearly distinguish it from its prokaryotic counterpart.