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-Structure paper
タイトル | The substrate specificity switch FlhB assembles onto the export gate to regulate type three secretion. |
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ジャーナル・号・ページ | Nat Commun, Vol. 11, Issue 1, Page 1296, Year 2020 |
掲載日 | 2020年3月10日 |
![]() | Lucas Kuhlen / Steven Johnson / Andreas Zeitler / Sandra Bäurle / Justin C Deme / Joseph J E Caesar / Rebecca Debo / Joseph Fisher / Samuel Wagner / Susan M Lea / ![]() ![]() |
PubMed 要旨 | Protein secretion through type-three secretion systems (T3SS) is critical for motility and virulence of many bacteria. Proteins are transported through an export gate containing three proteins ...Protein secretion through type-three secretion systems (T3SS) is critical for motility and virulence of many bacteria. Proteins are transported through an export gate containing three proteins (FliPQR in flagella, SctRST in virulence systems). A fourth essential T3SS protein (FlhB/SctU) functions to "switch" secretion substrate specificity once the growing hook/needle reach their determined length. Here, we present the cryo-electron microscopy structure of an export gate containing the switch protein from a Vibrio flagellar system at 3.2 Å resolution. The structure reveals that FlhB/SctU extends the helical export gate with its four predicted transmembrane helices wrapped around FliPQR/SctRST. The unusual topology of the FlhB/SctU helices creates a loop wrapped around the bottom of the closed export gate. Structure-informed mutagenesis suggests that this loop is critical in gating secretion and we propose that a series of conformational changes in the T3SS trigger opening of the gate through interactions between FlhB/SctU and FliPQR/SctRST. |
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手法 | EM (単粒子) |
解像度 | 3.2 - 4.1 Å |
構造データ | EMDB-10093, PDB-6s3l: EMDB-10095, PDB-6s3r: EMDB-10096, PDB-6s3s: ![]() EMDB-10653: |
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