Complete structure of the chemosensory array core signalling unit in an E. coli minicell strain
Complete structure of the chemosensory array core signalling unit in an E. coli minicell strain
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DOI：
10.1038/s41467-020-14350-9
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发表时间：
2020-02-06
影响因子：
16.6
通讯作者：
Gutsche, Irina
中科院分区：
文献类型：
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作者：
Burt, Alister;Cassidy, C. Keith;Gutsche, Irina
可运动细菌通过排列成超分子信号阵列的跨膜受体感知化学梯度。要在分子水平上理解刺激的检测与传递，需要对被称为核心信号单元的阵列构建模块进行精确的结构表征。在此，我们介绍一种大肠杆菌菌株，它能形成带有延伸且高度有序的化学感应阵列的小型微小细胞。我们利用冷冻电子断层扫描技术和子断层图平均法，绘制出完整核心信号单元的三维图谱，图谱中可见对应于HAMP结构域和周质结构域的密度。结合先前测定的高分辨率结构和分子动力学模拟，这一图谱产生了跨膜核心信号单元的分子模型，并能对其各个结构域进行空间定位。因此，我们的研究为解读大量现有数据以及设计进一步实验以阐明核心信号单元和更大阵列内的信号传导机制提供了坚实的结构基础。
Motile bacteria sense chemical gradients with transmembrane receptors organised in supramolecular signalling arrays. Understanding stimulus detection and transmission at the molecular level requires precise structural characterisation of the array building block known as a core signalling unit. Here we introduce an Escherichia coli strain that forms small minicells possessing extended and highly ordered chemosensory arrays. We use cryo-electron tomography and subtomogram averaging to provide a three-dimensional map of a complete core signalling unit, with visible densities corresponding to the HAMP and periplasmic domains. This map, combined with previously determined high resolution structures and molecular dynamics simulations, yields a molecular model of the transmembrane core signalling unit and enables spatial localisation of its individual domains. Our work thus offers a solid structural basis for the interpretation of a wide range of existing data and the design of further experiments to elucidate signalling mechanisms within the core signalling unit and larger array.