Whelan J, Tanudji M R, Smith M K, Day D A
Department of Biochemistry, University of Western Australia, Nedlands, Perth, Australia.
Biochim Biophys Acta. 1996 Jun 5;1312(1):48-54. doi: 10.1016/0167-4889(96)00014-6.
The effect of metal chelators on protein import was investigated using isolated soybean mitochondria and soybean precursor proteins. Adding 1,10-phenanthroline, a metal chelator that can cross both mitochondrial membranes abolished import of both the alternative oxidase, and the F(A)d subunit of the ATP synthase, a matrix located protein. Other metal chelators such as EDTA, 1,7-phenanthroline and 4,7-phenanthroline, which cannot cross the mitochondrial membranes, had no effect on import. When processing, a known metal-dependent step inside mitochondria, was inhibited using a mutagenesis approach (changing a -2 arginine to a -2 glycine in the pre-piece of the precursor), so was import. Thus it would appear that in soybean, at least, translocation of proteins across the mitochondrial membrane, as well as processing, relies on a metal dependent step. Taken together, the data suggest the two processes may be directly connected in these mitochondria.
利用分离的大豆线粒体和大豆前体蛋白，研究了金属螯合剂对蛋白质导入的影响。添加1,10 - 菲咯啉（一种能够穿过两层线粒体膜的金属螯合剂）后，交替氧化酶和位于线粒体基质中的ATP合酶F(A)d亚基的导入均被阻断。其他不能穿过线粒体膜的金属螯合剂，如EDTA、1,7 - 菲咯啉和4,7 - 菲咯啉，对蛋白质导入没有影响。当使用诱变方法（将前体蛋白前导肽中的 - 2位精氨酸变为 - 2位甘氨酸）抑制线粒体内部已知的金属依赖性步骤——加工时，蛋白质导入也受到抑制。因此，至少在大豆中，蛋白质穿过线粒体膜的转运以及加工似乎都依赖于一个金属依赖性步骤。综上所述，数据表明这两个过程在这些线粒体中可能直接相关。
