The 3-oxoacyl-CoA thiolases catalyze the last step of the fatty acid β-oxidation pathway. In yeasts and plants, this pathway takes place exclusively in peroxisomes, whereas in animals it occurs in both peroxisomes and mitochondria. In contrast to baker's yeast Saccharomyces cerevisiae, yeast species from the Debaryomycetaceae family also encode a thiolase with predicted mitochondrial localization. These yeasts are able to utilize a range of hydroxyaromatic compounds via the 3-oxoadipate pathway the last step of which is catalyzed by 3-oxoadipyl-CoA thiolase and presumably occurs in mitochondria. In this work, we studied Oct1p, an ortholog of this enzyme from Candida parapsilosis. We found that the cells grown on a 3-oxoadipate pathway substrate exhibit increased levels of the OCT1 mRNA. Deletion of both OCT1 alleles impairs the growth of C. parapsilosis cells on 3-oxoadipate pathway substrates and this defect can be rescued by expression of the OCT1 gene from a plasmid vector. Subcellular localization experiments and LC-MS/MS analysis of enriched organellar fraction-proteins confirmed the presence of Oct1p in mitochondria. Phylogenetic profiling of Oct1p revealed an intricate evolutionary pattern indicating multiple horizontal gene transfers among different fungal groups.

中文翻译：

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OCT1 – 一种参与 3-氧代己二酸途径的酵母线粒体硫解酶

3-氧代酰基辅酶A硫解酶催化脂肪酸β-氧化途径的最后一步。在酵母和植物中，该途径仅发生在过氧化物酶体中，而在动物中，它同时存在于过氧化物酶体和线粒体中。与面包酵母Saccharomyces cerevisiae 相比，Debaromycetaceae家族的酵母物种也编码具有预测线粒体定位的硫解酶。这些酵母能够通过 3-氧代己二酸途径利用一系列羟基芳香化合物，该途径的最后一步由 3-氧代己二酸-CoA 硫解酶催化，并且可能发生在线粒体中。在这项工作中，我们研究了来自近平滑念珠菌的这种酶的直系同源物 Oct1p. 我们发现在 3-氧代己二酸通路底物上生长的细胞表现出增加的OCT1 mRNA 水平。删除两个OCT1等位基因会损害近平滑念珠菌细胞在 3-氧代己二酸途径基质上的生长，并且可以通过从质粒载体表达OCT1基因来挽救这种缺陷。亚细胞定位实验和 LC-MS/MS 分析富集的细胞器级分蛋白质证实了线粒体中 Oct1p 的存在。Oct1p 的系统发育分析揭示了一个复杂的进化模式，表明不同真菌群之间的多个水平基因转移。