Hönlinger A, Keil P, Nelson R J, Craig E A, Pfanner N
Biochemisches Institut, Universität Freiburg, Germany.
Biol Chem Hoppe Seyler. 1995 Aug;376(8):515-9.
Posttranslational import of preproteins into mitochondria has been reported to be inefficient in a homologous yeast in vitro system, suggesting a requirement for coupling of protein synthesis and import. We have characterized a homologous yeast in vitro system which allows posttranslational mitochondrial import of preproteins. The efficiency is comparable to that of the heterologous system with rabbit reticulocyte lysate and isolated yeast mitochondria. Import in the homologous system depends on mitochondrial surface receptors, a membrane potential and the matrix heat shock protein Hsp70. Import is not blocked by the protein synthesis inhibitor cycloheximide, but is impaired by induction of stable folding in preproteins. Our studies demonstrate a posttranslational translocation mechanism in the homologous system, strongly supporting the validity of conclusions drawn from the widely used heterologous import system.
据报道，在前体蛋白的翻译后导入到线粒体的过程中，在同源酵母体外系统中效率低下，这表明需要将蛋白质合成与导入相偶联。我们已经鉴定了一种同源酵母体外系统，该系统允许前体蛋白进行翻译后线粒体导入。其效率与使用兔网织红细胞裂解物和分离的酵母线粒体的异源系统相当。同源系统中的导入取决于线粒体表面受体、膜电位和基质热休克蛋白Hsp70。导入不受蛋白质合成抑制剂环己酰亚胺的阻断，但会因前体蛋白中稳定折叠的诱导而受损。我们的研究证明了同源系统中的翻译后转运机制，有力地支持了从广泛使用的异源导入系统得出的结论的有效性。
