Phospholipase C (PLC),an important cell-signaling molecule,plays a critical role in GTP-binding protein mediated signal transduction pathways in plants and animals under environmental stress or pathogen invasion.As a unicellular phytoplankton,Emiliania huxleyi grows directly upon the completion of a cell cycle,during which cell signaling leads to the regulation of cellular metabolism and primary production,and responds to the environmental changes.However,phytoplankton phospholipase C and its involvement in signaling pathways remain unknown.By searching and compare the NCBI gene database keyword,we screened out 30 PLC proteins of E.huxleyi (EhPLC).By analyzing in conserved domain with the SMART (Simple Modular Architecture Research Tool) online,the 30 PLCs could be divided into four categories.In addition,we analyzed the systematic bioinformatics,including signal peptide,transmembrane domain,primary structure,secondary structure,tertiary structure,and cell localization.Certain differences are found in the signal peptide and transmembrane region of these amino acids;and all these PLCs have a-helix,β-sheet,and random coil in the secondary structure domain,and are located in the mitochondria.However,similarity in the tertiary structure is not obvious.In system evolutionary relationship,EhPLC is more intimate to protozoon other than plants.Therefore,the new findings would enrich the network system of plant in PLC signal transduction and provide tools for understanding relationship between PLC cell localization and signal pathways at an environmental stress.%磷脂酶C (phospholipase C,PLC)作为一种重要的细胞信号分子,是G蛋白信号转导过程中的重要调节因子之一,在动、植物环境胁迫应答及病原菌致病过程中发挥重要作用.海洋浮游植物生长代谢与环境因子之间的相互作用涉及细胞内复杂的信号通路,并最终通过调节细胞分裂过程控制浮游植物的增殖、种群生长动力及初级生产力.但对浮游植物PLC及其参与的信号通路的了解却非常少.通过NCBI基因数据库的关键词搜索、比对,发现海洋球石藻(Emiliania huxleyi)中含有30种PLC蛋白,利用SMART程序预测其结构保守域,以此将30种PLC分为四大类;对其氨基酸序列的信号肽、跨膜结构域、一级结构、二级结构、三级结构及其细胞定位等进行了生物信息学分析和预测.结果表明,海洋球石藻PLC具有丰富的多样性,它们在信号肽、跨膜区等方面均有一定的差别,其一级结构中存在多个可能的磷酸化修饰位点.二级结构中都含有α螺旋,β折叠,无规则卷曲,且都定位于线粒体,而三级结构相似度不高.从亲缘关系上看,海洋球石藻PLC与低等动物更接近.该研究补充和完善了对植物PLC信号转导网络系统的认识,并为进一步开展海洋球石藻PLC细胞定位及其参与的信号通路与环境胁迫之间关系的研究提供了重要的理论指导.
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