Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106–9510, USA.
J Mol Biol. 2012 Sep 14;422(2):282-90. doi: 10.1016/j.jmb.2012.05.023. Epub 2012 May 30.
In bacterial chemotaxis, transmembrane chemoreceptors, the CheA histidine kinase, and the CheW coupling protein assemble into signaling complexes that allow bacteria to modulate their swimming behavior in response to environmental stimuli. Among the protein-protein interactions in the ternary complex, CheA-CheW and CheW-receptor interactions were studied previously, whereas CheA-receptor interaction has been less investigated. Here, we characterize the CheA-receptor interaction in Thermotoga maritima by NMR spectroscopy and validate the identified receptor binding site of CheA in Escherichia coli chemotaxis. We find that CheA interacts with a chemoreceptor in a manner similar to that of CheW, and the receptor binding site of CheA's regulatory domain is homologous to that of CheW. Collectively, the receptor binding sites in the CheA-CheW complex suggest that conformational changes in CheA are required for assembly of the CheA-CheW-receptor ternary complex and CheA activation.
在细菌趋化作用中，跨膜化学感受器、CheA 组氨酸激酶和 CheW 偶联蛋白组装成信号复合物，使细菌能够根据环境刺激调节其游动行为。在三元复合物中的蛋白质-蛋白质相互作用中，以前研究了 CheA-CheW 和 CheW-受体相互作用，而 CheA-受体相互作用的研究较少。在这里，我们通过 NMR 光谱法对海洋栖热菌中的 CheA-受体相互作用进行了表征，并验证了 CheA 在大肠杆菌趋化作用中的鉴定受体结合位点。我们发现 CheA 以类似于 CheW 的方式与受体相互作用，并且 CheA 的调节域的受体结合位点与 CheW 的受体结合位点同源。总的来说，CheA-CheW 复合物中的受体结合位点表明，CheA 的构象变化是组装 CheA-CheW-受体三元复合物和 CheA 激活所必需的。
