Multiple catalase genes are differentially regulated in Aspergillus nidulans
Multiple catalase genes are differentially regulated in Aspergillus nidulans
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DOI：
10.1128/jb.183.4.1434-1440.2001
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发表时间：
2001-02-01
影响因子：
3.2
通讯作者：
Aguirre, J
中科院分区：
文献类型：
--
作者：
Kawasaki, L;Aguirre, J
过氧化氢的脱乙酰化是细胞抗氧化反应的一个基本方面，其中过氧化氢酶起主要作用。两个差异调节过氧化氢酶基因，catA和catB，已被研究构巢曲霉。在这里，我们的特点是第三个过氧化氢酶基因，指定catC，它预测一个475个氨基酸的多肽含有过氧化物酶体靶向信号。CatC的分子量为54 kDa，与其他小亚基单功能过氧化氢酶具有高度相似性，与其他真菌、真菌和动物的过氧化氢酶关系最为密切。相反，CatA（类似于84 kDa）和CatB（类似于79 kDa）酶属于大亚基过氧化氢酶家族，构成了独特的真菌和细菌组。catC基因表现出相对恒定的表达模式，不受氧化或其他类型的应激诱导。有针对性的破坏catC消除了组成型过氧化氢酶活性没有检测到以前的酶谱凝胶。然而，在稳定期后期在catA catB突变体菌株中检测到的过氧化氢酶活性仍然存在于catC和catABC无效突变体中，从而证明存在第四种过氧化氢酶，在此称为过氧化氢酶D（CatD）。catC和catABC三重突变体均未显示出任何发育缺陷，并且这两种突变体在H2 O2生成底物（如脂肪酸和/或嘌呤作为唯一碳源和氮源）中分别生长以及野生型菌株。CatD活性诱导葡萄糖饥饿，高温，并在较小程度上，H2 O2处理在后期稳定期。至少有四个差异调节过氧化氢酶的存在表明了一个大的和调节的能力，在丝状真菌的过氧化氢解毒。
Detoxification of hydrogen peroxide is a fundamental aspect of the cellular antioxidant responses in which catalases play a major role. Two differentially regulated catalase genes, catA and catB, have been studied in Aspergillus nidulans. Here we have characterized a third catalase gene, designated catC, which predicts a 475-amino acid polypeptide containing a peroxisome-targeting signal. With a molecular mass of 54 kDa, CatC shows high similarity to other small-subunit monofunctional catalases and is most closely related to catalases from other fungi, Archaea, and animals. In contrast, the CatA (similar to 84 kDa) and CatB (similar to 79 kDa) enzymes belong to a family of large-subunit catalases, constituting a unique fungal and bacterial group. The catC gene displayed a relatively constant pattern of expression, not being induced by oxidative or other types of stress. Targeted disruption of catC eliminated a constitutive catalase activity not detected previously in zymogram gels. However, a catalase activity detected in catA catB mutant strains during late stationary phase was still present in catC and catABC null mutants, thus demonstrating the presence of a fourth catalase, here named catalase D (CatD). Neither catC nor catABC triple mutants showed any developmental defect, and both mutants grew as well as wild-type strains in H2O2-generating substrates, such as fatty acids, and/or purines as the sole carbon and nitrogen sources, respectively. CatD activity was induced during late stationary phase by glucose starvation, high temperature, and, to a lesser extent, H2O2 treatment. The existence of at least four differentially regulated catalases indicates a large and regulated capability for H2O2 detoxification in filamentous fungi.