ᅟ: We report a protein sequence analysis of the cell cycle regulatory protease, separase. The sequence and structural conservation of the C-terminal protease domain has long been recognized, whereas the N-terminal regulatory domain of separase was reported to lack detectable sequence similarity. Here we reveal significant sequence conservation of the separase regulatory domain and report a discovery of a cysteine motif (CxCxxC) conserved in major lineages of Metazoa including nematodes and vertebrates. This motif is found in a solvent exposed linker region connecting two TPR-like helical motifs. Mutation of this motif in Caenorhabditis elegans separase leads to a temperature sensitive hypomorphic protein. Conservation of this motif in organisms ranging from C. elegans to humans suggests its functional importance. REVIEWERS This article was reviewed by Lakshminarayan Iyer and Michael Galperin.

中文翻译：

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分离酶调节域的保守。

ᅟ：我们报告了细胞周期调控蛋白酶separase的蛋白质序列分析。早已认识到C端蛋白酶结构域的序列和结构保守性，而据报道分离酶的N端调节结构域缺乏可检测的序列相似性。在这里，我们揭示了分离酶调节域的重要序列保守性，并报告了在后生动物的主要谱系（包括线虫和脊椎动物）中保守的半胱氨酸基序（CxCxxC）的发现。在连接两个TPR样螺旋基序的溶剂暴露的接头区域中发现此基序。秀丽隐杆线虫分离酶中该基序的突变导致温度敏感的亚型蛋白。从秀丽隐杆线虫到人类，这种基序在生物体中的保守性表明了其功能重要性。