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首页> 外文期刊>Molecular and Cellular Biology >Structural gene for ornithine decarboxylase in Neurospora crassa.
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Structural gene for ornithine decarboxylase in Neurospora crassa.

机译：景天孢菌中鸟氨酸脱羧酶的结构基因。

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To define the structural gene for ornithine decarboxylase (ODC) in Neurospora crassa, we sought mutants with kinetically altered enzyme. Four mutants, PE4, PE7, PE69, and PE85, were isolated. They were able to grow slowly at 25 degrees C on minimal medium but required putrescine or spermidine supplementation for growth at 35 degrees C. The mutants did not complement with one another or with ODC-less spe-1 mutants isolated in earlier studies. In all of the mutants isolated to date, the mutations map at the spe-1 locus on linkage group V. Strains carrying mutations PE4, PE7, and PE85 displayed a small amount of residual ODC activity in extracts. None of them had a temperature-sensitive enzyme. The enzyme of the PE85 mutant had a 25-fold higher Km for ornithine (5mM) than did the enzyme of wild-type or the PE4 mutant (ca. 0.2 mM). The enzyme of this mutant was more stable to heat than was the wild-type enzyme. These characteristics were normal in the mutant carrying allele PE4. The mutant carrying PE85 was able to grow well at 25 degrees C and weakly at 35 degrees C with ornithine supplementation. This mutant and three ODC-less mutants isolated previously displayed a polypeptide corresponding to ODC in Western immunoblots with antibody raised to purified wild-type ODC. We conclude that spe-1 is the structural gene for the ODC.
机译：若要定义在神经孢霉中的鸟氨酸脱羧酶（ODC）的结构基因，我们寻找具有动态改变的酶的突变体。分离了四个突变体，即PE4，PE7，PE69和PE85。它们能够在基本培养基上在25摄氏度下缓慢生长，但需要补充腐胺或亚精胺才能在35摄氏度下生长。这些突变体彼此之间没有互补，也没有与早期研究中分离出的无ODC的spe-1突变体互补。在迄今为止分离的所有突变体中，突变位于连接群V的spe-1位点。携带突变PE4，PE7和PE85的菌株在提取物中表现出少量的残留ODC活性。他们都没有对温度敏感的酶。 PE85突变体的酶对鸟氨酸（5mM）的Km值比野生型或PE4突变体的酶（约0.2 mM）高25倍。该突变体的酶比野生型酶对热更稳定。这些特征在携带等位基因PE4的突变体中是正常的。携带鸟氨酸的突变体在补充鸟氨酸的情况下能够在25摄氏度下良好生长，在35摄氏度下较弱。先前分离出的该突变体和三个无ODC的突变体在Western免疫印迹中显示对应于ODC的多肽，并带有针对纯化的野生型ODC的抗体。我们得出的结论是，spe-1是ODC的结构基因。

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