Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London, UK.
EMBO Rep. 2010 Dec;11(12):936-42. doi: 10.1038/embor.2010.164. Epub 2010 Nov 12.
The eukaryotic exosome is a key nuclease for the degradation, processing and quality control of a wide variety of RNAs. Here, we report electron microscopic reconstructions and pseudo-atomic models of the ten-subunit Saccharomyces cerevisiae exosome in the unbound and RNA-bound states. In the RNA-bound structures, extra density that is visible at the entry and exit sites of the exosome channel indicates that a substrate-threading mechanism is used by the eukaryotic exosome. This channelling mechanism seems to be conserved in exosome-like complexes from all domains of life, and might have been present in the most recent common ancestor.
真核生物核酶体是降解、加工和质量控制各种 RNA 的关键核酶。在这里,我们报告了未结合和 RNA 结合状态下十个亚基酿酒酵母核酶体的电子显微镜重构和拟原子模型。在 RNA 结合结构中,核酶体通道进出口处可见的额外密度表明,真核核酶体使用底物穿线机制。这种通道机制似乎在所有生命领域的核酶体样复合物中都保守存在,并且可能存在于最近的共同祖先中。