Non-intein splicing of RB47 - Activation of an Endoribonuclease by Non-intein Protein Splicing

The poly A binding protein RB47 was purified from C. reinhardtii chloroplasts and was found to have endoribonuclease activity. MS analysis suggested that an internal non-conserved linker (NCL)sequence was absent from the native protein. Recombinant, full length RB47 protein, including the NCL did not have endoribonuclease activity while versions lacking the NCL were active. An in vitro system, utilizing recombinant RB47 and chloroplast lysates, recreated the processing of RB47 in that the NCL was excised and the flanking sequences were spliced together.

从莱茵衣藻（C. reinhardtii）叶绿体中纯化得到的聚腺苷酸结合蛋白（poly A binding protein）RB47，被发现具有核糖核酸内切酶活性。质谱（MS）分析表明，该天然蛋白缺失一段内部非保守连接序列（NCL）。包含该NCL的重组全长RB47蛋白不具备核糖核酸内切酶活性，而缺失NCL的重组蛋白则具有该酶活性。利用重组RB47与叶绿体裂解液构建的体外系统，成功重现了RB47的加工过程：NCL被切除，其侧翼序列被拼接为一体。