Li Gao-Peng, Jiang Liang, Ni Jia-Zuan, Liu Qiong, Zhang Yan
Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, P, R, China.
BMC Genomics. 2014 Oct 17;15(1):908. doi: 10.1186/1471-2164-15-908.
Selenium (Se) and sulfur (S) are closely related elements that exhibit similar chemical properties. Some genes related to S metabolism are also involved in Se utilization in many organisms. However, the evolutionary relationship between the two utilization traits is unclear.
In this study, we conducted a comparative analysis of the selenophosphate synthetase (SelD) family, a key protein for all known Se utilization traits, in all sequenced archaea. Our search showed a very limited distribution of SelD and Se utilization in this kingdom. Interestingly, a SelD-like protein was detected in two orders of Crenarchaeota: Sulfolobales and Thermoproteales. Sequence and phylogenetic analyses revealed that SelD-like protein contains the same domain and conserved functional residues as those of SelD, and might be involved in S metabolism in these S-reducing organisms. Further genome-wide analysis of patterns of gene occurrence in different thermoproteales suggested that several genes, including SirA-like, Prx-like and adenylylsulfate reductase, were strongly related to SelD-like gene. Based on these findings, we proposed a simple model wherein SelD-like may play an important role in the biosynthesis of certain thiophosphate compound.
Our data suggest novel genes involved in S metabolism in hyperthermophilic S-reducing archaea, and may provide a new window for understanding the complex relationship between Se and S metabolism in archaea.
硒（Se）和硫（S）是密切相关的元素，具有相似的化学性质。在许多生物体中，一些与硫代谢相关的基因也参与硒的利用。然而，这两种利用特性之间的进化关系尚不清楚。
在本研究中，我们对所有已测序古菌中硒代磷酸合成酶（SelD）家族进行了比较分析，SelD家族是所有已知硒利用特性的关键蛋白。我们的搜索结果显示，SelD和硒利用在古菌界的分布非常有限。有趣的是，在泉古菌门的两个目（硫化叶菌目和热变形菌目）中检测到一种类似SelD的蛋白。序列和系统发育分析表明，类似SelD的蛋白与SelD含有相同的结构域和保守的功能残基，可能参与这些硫还原生物体中的硫代谢。对不同热变形菌目基因出现模式的进一步全基因组分析表明，包括类SirA、类Prx和腺苷硫酸还原酶在内的几个基因与类似SelD的基因密切相关。基于这些发现，我们提出了一个简单的模型，其中类似SelD的蛋白可能在某些硫代磷酸化合物的生物合成中起重要作用。
我们的数据表明，嗜热硫还原古菌中存在参与硫代谢的新基因，这可能为理解古菌中硒和硫代谢的复杂关系提供一个新的窗口。
