Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
Proc Natl Acad Sci U S A. 2011 Sep 13;108(37):15179-83. doi: 10.1073/pnas.1105921108. Epub 2011 Sep 6.
Mitochondrial protein import requires cooperation of the machineries called translocators in the outer and inner mitochondrial membranes. Here we analyze the interactions of Tom22, a multifunctional subunit of the outer membrane translocator TOM40 complex, with other translocator subunits such as Tom20, Tom40, and Tim50 and with substrate precursor proteins at a spatial resolution of the amino acid residue by in vivo and in organello site-specific photocross-linking. Changes in cross-linking patterns caused by excess substrate precursor proteins or presequence peptides indicate how the cytosolic receptor domain of Tom22 accepts substrate proteins and how the intermembrane space domain of Tom22 transfers them to Tim50 of the inner-membrane translocator.
线粒体蛋白的输入需要内外膜上的称为转位体的机器协同作用。在这里，我们以氨基酸残基的空间分辨率通过体内和细胞器特异性光交联分析了外膜转位体 TOM40 复合物的多功能亚基 Tom22 与其他转位体亚基（如 Tom20、Tom40 和 Tim50）以及与底物前体蛋白的相互作用。过量的底物前体蛋白或前导肽引起的交联模式变化表明 Tom22 的胞质受体结构域如何接受底物蛋白，以及 Tom22 的膜间空间结构域如何将它们转移到内膜转位体的 Tim50。
