New insights into bacterial chemoreceptor array structure and assembly from electron cryotomography.
New insights into bacterial chemoreceptor array structure and assembly from electron cryotomography.
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DOI：
10.1021/bi5000614
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发表时间：
2014-03-18
期刊：
影响因子：
2.9
通讯作者：
Jensen GJ
中科院分区：
文献类型：
--
作者：
Briegel A;Wong ML;Hodges HL;Oikonomou CM;Piasta KN;Harris MJ;Fowler DJ;Thompson LK;Falke JJ;Kiessling LL;Jensen GJ
细菌化学感受器聚集在高度有序的、合作的、具有保守结构的扩展阵列中，但管理阵列组装的原理仍不清楚。在这里，我们展示了细胞阵列的图像以及在体外重组的选定的化学感受器复合体，揭示了阵列结构和组装的新原理。首先，在每种情况下，受体都聚集在二聚体的三聚体配置中，这表明这是一种非常受欢迎的基本构件。其次，这些受体二聚体的三聚体在它们彼此之间以及与信号通路的其他组件之间形成的接触类型上表现出极大的多功能性，尽管在天然阵列中只有一种结构类型。第三，薄膜虽然可能加速阵列的形成，但对于晶格的形成既不是必要的，也不是充分的。分子拥挤取代了细胞膜的稳定作用，并允许细胞质受体片段形成与某些细菌物种中发现的细胞质化学受体阵列非常相似的夹心晶格。最后，阵列结构的有效决定因素似乎是CHEA和CHEW，它们形成了一个交替的CHEA填充环和CHEA空环的“超晶格”，将二聚体的受体三聚体单元连接到它们的天然六角晶格中。当伴随着受体、CHEA和CHEW的过度表达产生具有自然间距的阵列时，CHEA的占有率更低和更无序，这表明由单个转录因子驱动的基因表达的时空协调可能对完整的顺序至关重要，或者阵列的过度生长可能触发拆解过程。本文所述结果为研究这种大分子复合体的组装中间体和组装机理提供了新的见解。
Bacterial chemoreceptors cluster in highly ordered, cooperative, extended arrays with a conserved architecture, but the principles that govern array assembly remain unclear. Here we show images of cellular arrays as well as selected chemoreceptor complexes reconstituted in vitro that reveal new principles of array structure and assembly. First, in every case, receptors clustered in a trimers-of-dimers configuration, suggesting this is a highly favored fundamental building block. Second, these trimers-of-receptor dimers exhibited great versatility in the kinds of contacts they formed with each other and with other components of the signaling pathway, although only one architectural type occurred in native arrays. Third, the membrane, while it likely accelerates the formation of arrays, was neither necessary nor sufficient for lattice formation. Molecular crowding substituted for the stabilizing effect of the membrane and allowed cytoplasmic receptor fragments to form sandwiched lattices that strongly resemble the cytoplasmic chemoreceptor arrays found in some bacterial species. Finally, the effective determinant of array structure seemed to be CheA and CheW, which formed a “superlattice” of alternating CheA-filled and CheA-empty rings that linked receptor trimers-of-dimer units into their native hexagonal lattice. While concomitant overexpression of receptors, CheA, and CheW yielded arrays with native spacing, the CheA occupancy was lower and less ordered, suggesting that temporal and spatial coordination of gene expression driven by a single transcription factor may be vital for full order, or that array overgrowth may trigger a disassembly process. The results described here provide new insights into the assembly intermediates and assembly mechanism of this massive macromolecular complex.
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影响因子：
3.6
作者：
Briegel A;Ames P;Gumbart JC;Oikonomou CM;Parkinson JS;Jensen GJ
通讯作者：
Jensen GJ
影响因子：
4.8
作者：
CHERVITZ, SA;FALKE, JJ
通讯作者：
FALKE, JJ
影响因子：
2.9
作者：
Bornhorst, JA;Falke, JJ
通讯作者：
Falke, JJ
影响因子：
3.6
作者：
Briegel, Ariane;Ding, H. Jane;Jensen, Grant J.
通讯作者：
Jensen, Grant J.
影响因子：
3
作者：
Kremer, JR;Mastronarde, DN;McIntosh, JR
通讯作者：
McIntosh, JR