A dimeric two-component receiver domain inhibits the σ54-dependent ATPase in DctD
A dimeric two-component receiver domain inhibits the σ54-dependent ATPase in DctD
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DOI：
10.1096/fj.00-0516fje
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发表时间：
2001-05-01
期刊：
影响因子：
4.8
通讯作者：
Nixon, BT
中科院分区：
文献类型：
--
作者：
Meyer, MG;Park, S;Nixon, BT
本文报道了苜蓿中华根瘤菌（Sinorhizobium melilotiD）一种细菌增强子结合蛋白DctD的一个片段在1.7 nm处的晶体结构。该片段包含蛋白质的双组分接收器模块和相邻的接头，其在天然蛋白质中将接收器结构域连接到σ54依赖性ATP酶结构域。该结构揭示了一种新的二聚化表面，序列分析表明该表面在4.5%的已知双组分受体结构域中是共同的。氨基酸取代变体的遗传、生化和结构数据表明，二聚体是抑制ATP酶结构域基础活性所必需的。因此，需要二聚化元件来维持“关闭”状态，并且其内的变化可以发出激活信号。DctD的磷酸化片段的分析超离心数据似乎排除了信号传导是通过受体结构域的单体化介导的简单模型。
We report the crystal structure of a fragment ofSinorhizobium melilotiDctD, a bacterial enhancer binding protein, at 1.7 Å. The fragment contains the protein's two‐component receiver module and adjacent linker, which in the native protein joins the receiver domain to a σ54‐dependent ATPase domain. The structure reveals a novel dimerization surface, which sequence analysis indicates is common to 4.5% of the known two‐component receiver domains. Genetic, biochemical, and structural data for amino acid substitution variants indicate that the dimer is necessary to inhibit the basal activity of the ATPase domain. The dimerization element is thus needed to maintain the “off” state, and changes within it may signal activation. Analytical ultracentrifugation data for the phosphorylated fragment of DctD appear to rule out the simple model that signaling is mediated via monomerization of the receiver domain.