Donzeau M, Káldi K, Adam A, Paschen S, Wanner G, Guiard B, Bauer M F, Neupert W, Brunner M
Institut für Physiologische Chemie der Universität München, Germany.
Cell. 2000 May 12;101(4):401-12. doi: 10.1016/s0092-8674(00)80850-8.
Tim23, a key component of the mitochondrial preprotein translocase, is anchored in the inner membrane by its C-terminal domain and exposes an intermediate domain in the intermembrane space that functions as a presequence receptor. We show that the N-terminal domain of Tim23 is exposed on the surface of the outer membrane. The two-membrane-spanning topology of Tim23 is a novel characteristic in membrane biology. By the simultaneous integration into two membranes, Tim23 forms contacts between the outer and inner mitochondrial membranes. Tethering the inner membrane translocase to the outer membrane facilitates the transfer of precursor proteins from the TOM complex to the TIM23 complex and increases the efficiency of protein import.
Tim23是线粒体前体蛋白转位酶的关键组成部分，通过其C末端结构域锚定在内膜中，并在膜间隙中暴露一个中间结构域，该结构域作为前序列受体发挥作用。我们发现Tim23的N末端结构域暴露在外膜表面。Tim23的跨两膜拓扑结构是膜生物学中的一个新特征。通过同时整合到两个膜中，Tim23形成线粒体外膜和内膜之间的接触。将内膜转位酶与外膜连接有助于前体蛋白从TOM复合体转移到TIM23复合体，并提高蛋白质导入的效率。
