Körte A, Forsbach V, Gottenöf T, Rödel G
Institut für Genetik und Mikrobiologie der Universität München, Federal Republic of Germany.
Mol Gen Genet. 1989 May;217(1):162-7. doi: 10.1007/BF00330956.
Translation of mitochondrial cytochrome b mRNA in yeast is activated by the product of the nuclear gene CBS1. CBS1 encodes a 27 kDa precursor protein, which is cleaved to a 24 kDa mature protein during the import into isolated mitochondria. The sequences required for mitochondrial import reside in the amino-terminal end of the CBS1 precursor. Deletion of the 76 amino-terminal amino acids renders the protein incompetent for mitochondrial import in vitro and non-functional in vivo. When present on a high copy number plasmid and under the control of a strong yeast promoter, biological function can be restored by this truncated derivative. This observation indicates that the CBS1 protein devoid of mitochondrial targeting sequences can enter mitochondria in vivo, possibly due to a bypass of the mitochondrial import system.
酵母中线粒体细胞色素b信使核糖核酸（mRNA）的翻译由核基因CBS1的产物激活。CBS1编码一种27千道尔顿的前体蛋白，在导入分离的线粒体过程中被切割成24千道尔顿的成熟蛋白。线粒体导入所需的序列位于CBS1前体的氨基末端。删除76个氨基末端氨基酸会使该蛋白在体外无法进行线粒体导入，在体内无功能。当存在于高拷贝数质粒上并受强酵母启动子控制时，这种截短的衍生物可恢复生物学功能。这一观察结果表明，缺乏线粒体靶向序列的CBS1蛋白可能由于绕过线粒体导入系统而在体内进入线粒体。
