Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
Department of Chemistry, Chair of Organic Chemistry II, Center for Integrated Protein Science (CIPSM), Technische Universität München, Garching, Germany.
Nat Struct Mol Biol. 2019 Oct;26(10):946-954. doi: 10.1038/s41594-019-0304-0. Epub 2019 Oct 3.
The ClpXP machinery is a two-component protease complex that performs targeted protein degradation in bacteria and mitochondria. The complex consists of the AAA+ chaperone ClpX and the peptidase ClpP. The hexameric ClpX utilizes the energy of ATP binding and hydrolysis to engage, unfold and translocate substrates into the catalytic chamber of tetradecameric ClpP, where they are degraded. Formation of the complex involves a symmetry mismatch, because hexameric AAA+ rings bind axially to the opposing stacked heptameric rings of the tetradecameric ClpP. Here we present the cryo-EM structure of ClpXP from Listeria monocytogenes. We unravel the heptamer-hexamer binding interface and provide novel insight into the ClpX-ClpP cross-talk and activation mechanism. Comparison with available crystal structures of ClpP and ClpX in different states allows us to understand important aspects of the complex mode of action of ClpXP and provides a structural framework for future pharmacological applications.
ClpXP 机器是一种由两个组件组成的蛋白酶复合物，可在细菌和线粒体中进行靶向蛋白降解。该复合物由 AAA+伴侣蛋白 ClpX 和肽酶 ClpP 组成。六聚体的 ClpX 利用 ATP 结合和水解的能量来结合、展开并将底物转运到十四聚体 ClpP 的催化腔内，在那里它们被降解。复合物的形成涉及到一个对称不匹配，因为六聚体的 AAA+环轴向结合到十四聚体 ClpP 的相对堆叠的七聚体环上。在这里，我们展示了来自单核细胞增生李斯特菌的 ClpXP 的冷冻电镜结构。我们揭示了七聚体-六聚体结合界面，并为 ClpX-ClpP 串扰和激活机制提供了新的见解。与不同状态下可用的 ClpP 和 ClpX 的晶体结构进行比较，使我们能够理解 ClpXP 复合物作用模式的重要方面，并为未来的药理学应用提供了一个结构框架。
