The PilZ domain is a receptor for the second messenger c-di-GMP - The PilZ domain protein YcgR controls motility in enterobacteria
The PilZ domain is a receptor for the second messenger c-di-GMP - The PilZ domain protein YcgR controls motility in enterobacteria
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DOI：
10.1074/jbc.c600179200
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发表时间：
2006-10-13
影响因子：
4.8
通讯作者：
Gomelsky, Mark
中科院分区：
文献类型：
--
作者：
Ryjenkov, Dmitri A.;Simm, Roger;Gomelsky, Mark
普遍存在的细菌第二信使c-di-GMP控制胞外多糖的合成、基于鞭毛和纤毛的运动、基因表达以及细菌与真核宿主的相互作用。除细菌纤维素酶外，c-di-GMP受体和最终靶点的身份仍然未知。最近，Amikam和Galperin（Amikam，D.，和Galperin，M.（2006）Bioinformatics 22，3-6）假设存在于细菌纤维素酶的BcsA亚基中的PilZ结构域在c-di-GMP结合中起作用。该假设已在此使用大肠杆菌PilZ结构域蛋白YcgR、其单独的PilZ结构域和来自木葡糖酸醋杆菌BcsA的PilZ结构域进行了测试。纯化YcgR，发现其与c-di-GMP紧密且特异性地结合，K-d为0.84 μ M。来自YcgR和BcsA的单个PilZ结构域也结合c-di-GMP，尽管亲和力较低，表明PilZ足以结合。在YcgR上进行的定点诱变暗示PilZ结构域中最保守的残基直接参与c-di-GMP结合。这表明c-di-GMP与PilZ的结合引起蛋白质的构象变化，其稳定结合的配体并启动下游信号转导级联。虽然YcgR的下游伴侣的身份仍然未知，但显示YcgR以c-di-GMP依赖性方式调节基于鞭毛的运动。ycgR的失活改善了运动性差的肠道沙门氏菌鼠伤寒血清型UMR 1的yhjH突变体的游泳和群集运动性。因此，本文提供的生物化学和遗传学证据确立PilZ是长期寻求的c-di-GMP结合结构域，YcgR是影响肠细菌运动性的c-di-GMP受体。
The ubiquitous bacterial second messenger c-di-GMP controls exopolysaccharide synthesis, flagella-and pili-based motility, gene expression, and interactions of bacteria with eukaryotic hosts. With the exception of bacterial cellulose synthases, the identities of c-di-GMP receptors and end targets have remained unknown. Recently, Amikam and Galperin (Amikam, D., and Galperin, M. (2006) Bioinformatics 22, 3-6) hypothesized that the PilZ domains present in the BcsA subunits of bacterial cellulose synthases function in c-di-GMP binding. This hypothesis has been tested here using the Escherichia coli PilZ domain protein YcgR, its individual PilZ domain and the PilZ domain from Gluconacetobacter xylinus BcsA. YcgR was purified and found to bind c-di-GMP tightly and specifically, K-d 0.84 mu M. Individual PilZ domains from YcgR and BcsA also bound c-di-GMP, albeit with lesser affinity, indicating that PilZ is sufficient for binding. The site-directed mutagenesis performed on YcgR implicated the most conserved residues in the PilZ domain directly in c-di-GMP binding. It is suggested that c-di-GMP binding to PilZ brings about conformational changes in the protein that stabilize the bound ligand and initiate the downstream signal transduction cascade. While the identity of the downstream partner(s) of YcgR remains unknown, it is shown that YcgR regulates flagellum-based motility in a c-di-GMP-dependent manner. The inactivation of ycgR improves swimming and swarming motility of the poorly motile yhjH mutants of Salmonella enterica serovar Typhimurium UMR1. Therefore, biochemical and genetic evidence presented here establishes PilZ as a long sought after c-di-GMP-binding domain and YcgR as a c-di-GMP receptor affecting motility in enterobacteria.