Galanis M, Devenish R J, Nagley P
Department of Biochemistry, Monash University, Clayton, Victoria, Australia.
FEBS Lett. 1991 May 6;282(2):425-30. doi: 10.1016/0014-5793(91)80529-c.
We describe a novel method for enhancing protein import into mitochondria, by tandemly duplicating the N-terminal cleavable leader peptide using a gene manipulation strategy. The import into isolated yeast mitochondria of passenger proteins (yeast mitochondrial ATP synthase subunits 8 and 9 and some mutagenised derivatives) that show little or no import when endowed with one such leader (that of Neurospora crassa mitochondrial ATP synthase subunit 9) is remarkably improved when the leader is tandemly duplicated. The import of these chimaeric proteins bearing a double leader is so rapid that a series of partially processed precursor intermediates accumulates inside the mitochondria before the final proteolytic release of leader sequences from the passenger proteins. It is considered that the duplicated leader greatly accelerates delivery of the import precursors to outer membrane receptor elements and the associated translocation systems, thereby enhancing precursor uptake into mitochondria.
我们描述了一种通过基因操作策略串联复制N端可裂解前导肽来增强蛋白质导入线粒体的新方法。携带一种这样的前导肽（粗糙脉孢菌线粒体ATP合酶亚基9的前导肽）时几乎没有或完全没有导入能力的客体蛋白（酵母线粒体ATP合酶亚基8和9以及一些诱变衍生物），当该前导肽串联复制时，其导入分离的酵母线粒体的能力得到显著改善。这些带有双前导肽的嵌合蛋白的导入速度非常快，以至于在客体蛋白的前导序列最终被蛋白水解释放之前，一系列部分加工的前体中间体会在线粒体内积累。据认为，复制的前导肽极大地加速了导入前体向线粒体外膜受体元件和相关转运系统的传递，从而增强了前体摄入线粒体的能力。
