Crystal structure of Spa40, the specificity switch for the Shigella flexneri type III secretion system.
Crystal structure of Spa40, the specificity switch for the Shigella flexneri type III secretion system.
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DOI：
10.1111/j.1365-2958.2008.06293.x
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发表时间：
2008-07
影响因子：
3.6
通讯作者：
Lea SM
中科院分区：
文献类型：
--
作者：
Deane JE;Graham SC;Mitchell EP;Flot D;Johnson S;Lea SM
致病细菌福氏志贺氏菌使用III型分泌系统将细菌胞浆中的毒力因子直接注入宿主细胞。识别分泌底物和控制细胞外成分和效应蛋白输出的机制由几种内膜和细胞质蛋白组成。内膜成分之一Spa40属于一个蛋白质家族，被认为调节输出装置底物专一性的开关。我们发现Spa40在严格保守的氨基酸序列NPTH内被切割，而所提出的自催化残基的替代取消了切割。我们还报道了细胞质复合体Spa40C的晶体结构，并将其与大肠杆菌和鼠伤寒沙门氏菌的同系物的最新结构进行了比较。这些结构揭示了被切割片段的紧密结合，并表明保守的NPTH序列位于一个环上，当被切割时，该环从催化的N257残基摆动，导致该区域不同的表面特征。这种结构重排表明了一种机制，通过这种机制，这些蛋白质的非裂解形式干扰了装置的正确底物切换。
The pathogenic bacterium Shigella flexneri uses a type III secretion system to inject virulence factors from the bacterial cytosol directly into host cells. The machinery that identifies secretion substrates and controls the export of extracellular components and effector proteins consists of several inner-membrane and cytoplasmic proteins. One of the inner membrane components, Spa40, belongs to a family of proteins proposed to regulate the switching of substrate specificity of the export apparatus. We show that Spa40 is cleaved within the strictly conserved amino acid sequence NPTH and substitution of the proposed autocatalytic residue abolishes cleavage. Here we also report the crystal structure of the cytoplasmic complex Spa40C and compare it with the recent structures of the homologues from Escherichia coli and Salmonella typhimurium. These structures reveal the tight association of the cleaved fragments and show that the conserved NPTH sequence lies on a loop which, when cleaved, swings away from the catalytic N257 residue, resulting in different surface features in this region. This structural rearrangement suggests a mechanism by which non-cleaving forms of these proteins interfere with correct substrate switching of the apparatus.
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DOI：
10.1083/jcb.147.3.683
发表时间：
1999-11-01
期刊：
The Journal of cell biology
影响因子：
--
作者：
Blocker A;Gounon P;Larquet E;Niebuhr K;Cabiaux V;Parsot C;Sansonetti P
通讯作者：
Sansonetti P
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
14.9
作者：
Davis IW;Leaver-Fay A;Chen VB;Block JN;Kapral GJ;Wang X;Murray LW;Arendall WB 3rd;Snoeyink J;Richardson JS;Richardson DC
通讯作者：
Richardson DC
影响因子：
14.9
作者：
Käll L;Krogh A;Sonnhammer EL
通讯作者：
Sonnhammer EL
影响因子：
3.6
作者：
FORSBERG, A;VIITANEN, AM;WOLFWATZ, H
通讯作者：
WOLFWATZ, H