Wu H, Hu Z, Liu X Q
Biochemistry Department, Dalhousie University, Halifax, Nova Scotia, B3H 4H7, Canada.
Proc Natl Acad Sci U S A. 1998 Aug 4;95(16):9226-31. doi: 10.1073/pnas.95.16.9226.
A split intein capable of protein trans-splicing is identified in a DnaE protein of the cyanobacterium Synechocystis sp. strain PCC6803. The N- and C-terminal halves of DnaE (catalytic subunit alpha of DNA polymerase III) are encoded by two separate genes, dnaE-n and dnaE-c, respectively. These two genes are located 745,226 bp apart in the genome and on opposite DNA strands. The dnaE-n product consists of a N-extein sequence followed by a 123-aa intein sequence, whereas the dnaE-c product consists of a 36-aa intein sequence followed by a C-extein sequence. The N- and C-extein sequences together reconstitute a complete DnaE sequence that is interrupted by the intein sequences inside the beta- and tau-binding domains. The two intein sequences together reconstitute a split mini-intein that not only has intein-like sequence features but also exhibited protein trans-splicing activity when tested in Escherichia coli cells.
在蓝藻集胞藻PCC6803株的DnaE蛋白中鉴定出一种能够进行蛋白质反式剪接的分裂内含肽。DnaE（DNA聚合酶III的催化亚基α）的N端和C端两半分别由两个独立的基因dnaE-n和dnaE-c编码。这两个基因在基因组中相距745,226 bp，位于相反的DNA链上。dnaE-n产物由一个N-外显肽序列和一个123个氨基酸的内含肽序列组成，而dnaE-c产物由一个36个氨基酸的内含肽序列和一个C-外显肽序列组成。N-外显肽序列和C-外显肽序列共同重构出一个完整的DnaE序列，该序列在β和τ结合域内被内含肽序列中断。这两个内含肽序列共同重构出一个分裂的小内含肽，它不仅具有类似内含肽的序列特征，而且在大肠杆菌细胞中进行测试时还表现出蛋白质反式剪接活性。
