Dekker P J, Müller H, Rassow J, Pfanner N
Institut für Biochemie und Molekularbiologie, Universität Freiburg, Germany.
Biol Chem. 1996 Jul-Aug;377(7-8):535-8.
The mitochondrial outer membrane contains import receptors for nuclear-encoded preproteins and a general import pore responsible for membrane translocation of preproteins. Receptors and the general import pore have been suggested to assemble into a loose complex. However, biochemical characterization of the complex has been limited so far. We report that blue native electrophoresis separates two complexes. One complex of approximately 400 kDa contains the receptor Tom22 and the general import pore component Tom40, the other complex of approximately 120 kDa contains the receptor Tom70. A preprotein accumulated at the general import pore apparently co-migrates with the larger complex, suggesting the functionality of the complex. We conclude that the translocase of the outer membrane consists of at least two subcomplexes and that blue native electrophoresis will be a powerful tool for biochemical analysis of the complexes.
线粒体外膜含有核编码前体蛋白的输入受体以及负责前体蛋白跨膜转运的通用输入孔。有观点认为受体和通用输入孔会组装成一个松散的复合体。然而，到目前为止，该复合体的生化特性研究还很有限。我们报告称，蓝色非变性电泳分离出两种复合体。一种约400 kDa的复合体包含受体Tom22和通用输入孔组件Tom40，另一种约120 kDa的复合体包含受体Tom70。在通用输入孔处积累的一种前体蛋白显然与较大的复合体共同迁移，这表明该复合体具有功能。我们得出结论，外膜转位酶至少由两个亚复合体组成，并且蓝色非变性电泳将成为分析这些复合体生化特性的有力工具。
