Functional roles of the pre-sensor I insertion sequence in an AAA+ bacterial enhancer binding protein.
Functional roles of the pre-sensor I insertion sequence in an AAA+ bacterial enhancer binding protein.
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AAA 细菌增强子结合蛋白中前传感器 I 插入序列的功能作用。
DOI：
10.1111/j.1365-2958.2009.06744.x
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发表时间：
2009
影响因子：
3.6
通讯作者：
Buck,Martin
中科院分区：
文献类型：
--
作者：
Burrows,PatriciaC;Schumacher,Jörg;Amartey,Samuel;Ghosh,Tamaswati;Burgis,TimothyA;Zhang,Xiaodong;Nixon,BTracy;Buck,Martin
属于AAA+ATPase超家族的分子机器使用NTP水解来重塑其多功能底物。插入序列的存在定义了主要的系统发育前传感器I插入(Pre-SII)AAA+超分支。在细菌σ54依赖的增强子结合蛋白噬菌体休克蛋白F(PspF)中，前SII环根据核苷酸结合状态而采用不同的构象。在PspF的动态Pre-SII环中，单个氨基酸的取代极大地改变了ATP的水解参数，表明了与远端水解点的结构联系。我们使用位点特异的蛋白质-DNA邻近分析来衡量前SII环在σ54依赖的转录中的作用，并证明前SII环是介导核苷酸状态依赖的与Eσ54差异结合的主要结构特征。我们认为，Pre-SII环的大部分(如果不是全部)的作用是通过L1环介导的，并依赖于一个保守的分子开关，该开关在一个Pre-SII变异体的晶体结构中被鉴定，并且与一些Pre-SII残基和Pre-SII序列之外的不同残基之间的高度协方差一致。
Molecular machines belonging to the AAA+ superfamily of ATPases use NTP hydrolysis to remodel their versatile substrates. The presence of an insertion sequence defines the major phylogenetic pre‐sensor I insertion (pre‐SIi) AAA+ superclade. In the bacterial σ54‐dependent enhancer binding protein phage shock protein F (PspF) the pre‐SIi loop adopts different conformations depending on the nucleotide‐bound state. Single amino acid substitutions within the dynamic pre‐SIi loop of PspF drastically change the ATP hydrolysis parameters, indicating a structural link to the distant hydrolysis site. We used a site‐specific protein–DNA proximity assay to measure the contribution of the pre‐SIi loop in σ54‐dependent transcription and demonstrate that the pre‐SIi loop is a major structural feature mediating nucleotide state‐dependent differential engagement with Eσ54. We suggest that much, if not all, of the action of the pre‐SIi loop is mediated through the L1 loop and relies on a conserved molecular switch, identified in a crystal structure of one pre‐SIi variant and in accordance with the high covariance between some pre‐SIi residues and distinct residues outside the pre‐SIi sequence.