Kiebler M, Keil P, Schneider H, van der Klei I J, Pfanner N, Neupert W
Institut für Physiologische Chemie, Universität München, Federal Republic of Germany.
Cell. 1993 Aug 13;74(3):483-92. doi: 10.1016/0092-8674(93)80050-o.
The receptor complex in the mitochondrial outer membrane, which consists of at least seven different proteins, is responsible for the recognition and translocation of cytosolically synthesized preproteins. Two of its subunits, MOM19 and MOM72, function as surface receptors for preproteins. Four other subunits (MOM38, MOM30, MOM8, and MOM7) have been suggested to constitute the general insertion pore (GIP). Here we report on the structure and function of MOM22. MOM22 is anchored in the outer membrane by a single transmembrane segment. The highly negatively charged N-terminal domain is exposed to the cytosol and the C-terminal domain to the intermembrane space. MOM22 appears to be a central component of the receptor complex, required for the transfer of preproteins from the receptors to the GIP. We speculate that the negatively charged domain of MOM22 is involved in the transfer of positively charged signal sequences of preproteins.
线粒体外膜中的受体复合物由至少七种不同的蛋白质组成，负责识别和转运在细胞质中合成的前体蛋白。其两个亚基，MOM19和MOM72，作为前体蛋白的表面受体发挥作用。另外四个亚基（MOM38、MOM30、MOM8和MOM7）被认为构成了通用插入孔（GIP）。在此，我们报告MOM22的结构和功能。MOM22通过单个跨膜片段锚定在外膜中。高度带负电荷的N端结构域暴露于细胞质中，而C端结构域暴露于膜间隙中。MOM22似乎是受体复合物的核心组成部分，是前体蛋白从受体转移到GIP所必需的。我们推测，MOM22带负电荷的结构域参与了前体蛋白带正电荷信号序列的转移。
