The enigmatic mitochondrial ORF ymf39 codes for ATP synthase chain b
The enigmatic mitochondrial ORF ymf39 codes for ATP synthase chain b
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DOI：
10.1093/nar/gkg326
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发表时间：
2003-05-01
影响因子：
14.9
通讯作者：
Marx, S
中科院分区：
文献类型：
--
作者：
Burger, G;Lang, BF;Marx, S
YMF 39是在陆地植物和某些原生生物的线粒体基因组中发现的保守的假定蛋白质编码基因。基于来自绿色根瘤菌的Ymf 39和来自慢生根瘤菌的atpF基因产物之间的弱序列相似性，我们推测ymf 39可能编码线粒体F0 F1-ATP合酶的亚基B。为了验证这一假设，我们对来自5种原始生物的ymf 39进行了测序，这些原始生物的线粒体基因组来源最少，即雅各布虫。此外，我们分离的线粒体ATP合酶复合物的jakobid Seculamonas厄瓜多尔，并确定了部分蛋白质序列的19 kDa的亚基，预计YMF 39的大小。所获得的肽序列与该生物体的ymf 39基因的3 ′-近端区域完全匹配，证实Ymf 39确实是ATP合酶亚基。最后，我们采用统计检验来评估Ymf 39蛋白质序列相似性的意义，它们的核编码的功能对应物，ATP 4/ATP 5 F，从真菌和动物和α-变形菌ATP合酶b-亚基。这项分析提供了明确的证据，表明ymf 39是atpF同源物，而ATP 4/ATP 5 F似乎是ymf 39的高度分化形式，已迁移到细胞核。我们建议从现在起将ymf 39命名为atp 4。
ymf39 is a conserved hypothetical protein-coding gene found in mitochondrial genomes of land plants and certain protists. We speculated earlier, based on a weak sequence similarity between Ymf39 from a green alga and the atpF gene product from Bradyrhizobium, that ymf39 might code for subunit b of mitochondrial F0F1-ATP synthase. To test this hypothesis, we have sequenced ymf39 from five protists with minimally derived mitochondrial genomes, the jakobids. In addition, we isolated the mitochondrial ATP synthase complex of the jakobid Seculamonas ecuadoriensis and determined the partial protein sequence of the 19-kDa subunit, the size expected for Ymf39. The obtained peptide sequence matches perfectly with a 3'-proximal region of the ymf39 gene of this organism, confirming that Ymf39 is indeed an ATP synthase subunit. Finally, we employed statistical tests to assess the significance of sequence similarity of Ymf39 proteins with each other, their nucleus-encoded functional counterparts, ATP4/ATP5F, from fungi and animals and alpha-proteobacterial ATP synthase b-subunits. This analysis provides clear evidence that ymf39 is an atpF homolog, while ATP4/ATP5F appears to be a highly diverged form of ymf39 that has migrated to the nucleus. We propose to designate ymf39 from now on atp4.