叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和...叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和内被膜的路径被传送进入叶绿体内部,进而到达发挥其生物学功能的目的微区。目前已知的前体蛋白转运的一个主要途径是通过叶绿体外被膜转运子(translocon in the outer envelope membrane of chloroplast, TOC)和内被膜转运子(translocon in the inner envelope membrane of chloroplast, TIC),在二者的协同作用下前体蛋白得以跨越双层被膜进入叶绿体。文章回顾了TOC-TIC超复合物的结构生物学研究进展,并深入探讨了各组件的功能特性以及前体蛋白易位至叶绿体内部的潜在途径和调控机制。展开更多
Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted ...Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted via Sec secretion pathway in Vibrio anguillarum. In this study, hetemlogous expression of the empA gene encoding metallopmtease and export of the recombinant metallopmtease in Escherichia coli were examined. The empA gene was subcloned into pBAD24 with arabinose promoter and sequenced. The sequence encoded a polypeptide （611 amino acids） consisting of four domains： a signal peptide, an Nterminal pmpoptide, a mature region and a C-terminal pmpoptide. The empA gene inserted in plasmid pBAD24 was overexpressed in TOP10 strain of E. coli after arabinose induction. The 36kDa polypeptide of the recombinant metallopmtease as the mature pmtease was further confirmed by SDS-PAGE and im- munoblotting. It was found that recombinant metallopmtease with the EmpA activity and antigenicity was exported into the poriplasm of Escherichia coli cells via Sec translocation pathway, whereas it was secreted into extracellular environments in V. anguillarum. The results imply that the expression, export and processing mechanism of the protein in E. coli are similar to those in V. anguillarum.展开更多
文摘叶绿体作为植物及藻类细胞中含有内外双层被膜的细胞器,能够通过光合作用过程将光能转化为化学能。大部分的叶绿体蛋白由细胞核基因编码,其前体蛋白是在细胞质中的80S核糖体上合成的。前体蛋白在转运肽的引导下,通过跨越叶绿体外被膜和内被膜的路径被传送进入叶绿体内部,进而到达发挥其生物学功能的目的微区。目前已知的前体蛋白转运的一个主要途径是通过叶绿体外被膜转运子(translocon in the outer envelope membrane of chloroplast, TOC)和内被膜转运子(translocon in the inner envelope membrane of chloroplast, TIC),在二者的协同作用下前体蛋白得以跨越双层被膜进入叶绿体。文章回顾了TOC-TIC超复合物的结构生物学研究进展,并深入探讨了各组件的功能特性以及前体蛋白易位至叶绿体内部的潜在途径和调控机制。
基金Supported by the National Natural Science Foundation of China （ No. 30328021 ）.
文摘Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted via Sec secretion pathway in Vibrio anguillarum. In this study, hetemlogous expression of the empA gene encoding metallopmtease and export of the recombinant metallopmtease in Escherichia coli were examined. The empA gene was subcloned into pBAD24 with arabinose promoter and sequenced. The sequence encoded a polypeptide （611 amino acids） consisting of four domains： a signal peptide, an Nterminal pmpoptide, a mature region and a C-terminal pmpoptide. The empA gene inserted in plasmid pBAD24 was overexpressed in TOP10 strain of E. coli after arabinose induction. The 36kDa polypeptide of the recombinant metallopmtease as the mature pmtease was further confirmed by SDS-PAGE and im- munoblotting. It was found that recombinant metallopmtease with the EmpA activity and antigenicity was exported into the poriplasm of Escherichia coli cells via Sec translocation pathway, whereas it was secreted into extracellular environments in V. anguillarum. The results imply that the expression, export and processing mechanism of the protein in E. coli are similar to those in V. anguillarum.
