The Linker between the Dimerization and Catalytic Domains of the CheA Histidine Kinase Propagates Changes in Structure and Dynamics That Are Important for Enzymatic Activity
详细信息 查看全文
- 作者：Xiqing Wang ; Pramodh Vallurupalli ; Anh Vu ; Kwangwoon Lee ; Sheng Sun ; Wen-Ju Bai ; Chun Wu ; Hongjun Zhou ; Joan-Emma Shea ; Lewis E. Kay ; Frederick W. Dahlquist
- 刊名：Biochemistry
- 出版年：2014
- 出版时间：February 11, 2014
- 年：2014
- 卷：53
- 期：5
- 页码：855-861
- 全文大小：321K
- ISSN：1520-4995
文摘
The histidine kinase, CheA, couples environmental stimuli to changes in bacterial swimming behavior, converting a sensory signal to a chemical signal in the cytosol via autophosphorylation. The kinase activity is regulated in the platform of chemotaxis signaling complexes formed by CheW, chemoreceptors, and the regulatory domain of CheA. Our previous computational and mutational studies have revealed that two interdomain linkers play important roles in CheA鈥檚 enzymatic activity. Of the two linkers, one that connects the dimerization and ATP binding domains is essential for both basal autophosphorylation and activation of the kinase. However, the mechanistic role of this linker remains unclear, given that it is far from the autophosphorylation reaction center (the ATP binding site). Here we investigate how this interdomain linker is coupled to CheA鈥檚 enzymatic activity. Using modern nuclear magnetic resonance (NMR) techniques, we find that by interacting with the catalytic domain, the interdomain linker initiates long-range structural and dynamic changes directed toward the catalytic center of the autophosphorylation reaction. Subsequent biochemical assays define the functional relevance of these NMR-based observations. These findings extend our understanding of the chemotaxis signal transduction pathway.