Chen Xin Jie, Wang Xiaowen, Butow Ronald A
Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA.
Proc Natl Acad Sci U S A. 2007 Aug 21;104(34):13738-43. doi: 10.1073/pnas.0703078104. Epub 2007 Aug 14.
Aconitase (Aco1p) is a multifunctional protein: It is an enzyme of the tricarboxylic acid cycle. In animal cells, Aco1p also is a cytosolic protein binding to mRNAs to regulate iron metabolism. In yeast, Aco1p was identified as a component of mtDNA nucleoids. Here we show that yeast Aco1p protects mtDNA from excessive accumulation of point mutations and ssDNA breaks and suppresses reductive recombination of mtDNA. Aconitase binds to both ds- and ssDNA, with a preference for GC-containing sequences. Therefore, mitochondria are opportunistic organelles that seize proteins, such as metabolic enzymes, for construction of the nucleoid, an mtDNA maintenance/segregation apparatus.
顺乌头酸酶（Aco1p）是一种多功能蛋白质：它是三羧酸循环中的一种酶。在动物细胞中，Aco1p也是一种与mRNA结合以调节铁代谢的胞质蛋白。在酵母中，Aco1p被鉴定为线粒体DNA类核的一个组成部分。在这里我们表明，酵母Aco1p可保护线粒体DNA免受点突变和单链DNA断裂的过度积累，并抑制线粒体DNA的还原重组。顺乌头酸酶可与双链和单链DNA结合，更倾向于含GC的序列。因此，线粒体是机会主义细胞器，会利用诸如代谢酶等蛋白质来构建类核，即一种线粒体DNA维持/分离装置。
