Diversity and functional plasticity of eukaryotic selenoproteins:: Identification and characterization of the SelJ family
Diversity and functional plasticity of eukaryotic selenoproteins:: Identification and characterization of the SelJ family
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DOI：
10.1073/pnas.0505146102
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发表时间：
2005-11-08
影响因子：
11.1
通讯作者：
Guigó, R
中科院分区：
文献类型：
--
作者：
Castellano, S;Lobanov, AV;Guigó, R
硒蛋白是一组含有硒代半胱氨酸（Sec）的蛋白质，第21位氨基酸。在遗传密码中，UGA作为终止信号和Sec密码子。这种双重作用排除了硒蛋白的自动注释。硒蛋白基因的计算机识别的最新进展提供了第一次瞥见的大小，功能和真核生物硒蛋白质组的系统发育多样性。在这里，我们描述了一个硒蛋白家族命名为SeIJ的鉴定。与已知的硒蛋白相反，SeIJ似乎仅限于actinopterygian鱼类和海胆，Cys同源物仅发现于cniclarians。SeIJ显示出与水母J1-晶体蛋白的显著相似性，并且与它们一起构成ADP-核糖基化酶大家族内的独特亚家族。与其作为结构晶体蛋白的潜在作用一致，SeIJ在斑马鱼发育的早期阶段在眼透镜中具有优先和均匀的表达。SeIJ的结构作用与大多数已知的硒酶相反。异常高度限制的系统发育分布的硒IJ，其专业化，和真核硒蛋白质组的比较分析揭示了硒蛋白质的多样性和功能可塑性，并指出马赛克的使用SEC的蛋白质的进化。
Selenoproteins are a diverse group of proteins that contain selenocysteine (Sec), the 21st amino acid. In the genetic code, UGA serves as a termination signal and a Sec codon. This dual role has precluded the automatic annotation of selenoproteins. Recent advances in the computational identification of selenoprotein genes have provided a first glimpse of the size, functions, and phylogenetic diversity of eukaryotic selenoproteomes. Here, we describe the identification of a selenoprotein family named SeIJ. In contrast to known selenoproteins, SeIJ appears to be restricted to actinopterygian fishes and sea urchin, with Cys homologues only found in cniclarians. SeIJ shows significant similarity to the jellyfish J1-crystallins and with them constitutes a distinct subfamily within the large family of ADP-ribosylation enzymes. Consistent with its potential role as a structural crystallin, SeIJ has preferential and homogeneous expression in the eye lens in early stages of zebrafish development. A structural role for SeIJ would be in contrast to the majority of known selenoenzymes. The unusually highly restricted phylogenetic distribution of SeIJ, its specialization, and the comparative analysis of eukaryotic selenoproteomes reveal the diversity and functional plasticity of selenoproteins and point to a mosaic evolution of the use of Sec in proteins.