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Type 9 secretion system structures reveal a new protein transport mechanism
Nature ( IF 50.5 ) Pub Date : 2018-11-07 , DOI: 10.1038/s41586-018-0693-y
Frédéric Lauber 1 , Justin C Deme 2, 3 , Susan M Lea 2, 3 , Ben C Berks 1
Nature ( IF 50.5 ) Pub Date : 2018-11-07 , DOI: 10.1038/s41586-018-0693-y
Frédéric Lauber 1 , Justin C Deme 2, 3 , Susan M Lea 2, 3 , Ben C Berks 1
Affiliation
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The type 9 secretion system (T9SS) is the protein export pathway of bacteria of the Gram-negative Fibrobacteres–Chlorobi–Bacteroidetes superphylum and is an essential determinant of pathogenicity in severe periodontal disease. The central element of the T9SS is a so-far uncharacterized protein-conducting translocon located in the bacterial outer membrane. Here, using cryo-electron microscopy, we provide structural evidence that the translocon is the T9SS protein SprA. SprA forms an extremely large (36-strand) single polypeptide transmembrane β-barrel. The barrel pore is capped on the extracellular end, but has a lateral opening to the external membrane surface. Structures of SprA bound to different components of the T9SS show that partner proteins control access to the lateral opening and to the periplasmic end of the pore. Our results identify a protein transporter with a distinctive architecture that uses an alternating access mechanism in which the two ends of the protein-conducting channel are open at different times.Cryo-electron microscopy structures of the protein-conducting translocon of the type 9 secretion system reveal its architecture and mechanism of translocation.
中文翻译:
9型分泌系统结构揭示了一种新的蛋白质转运机制
9 型分泌系统 (T9SS) 是革兰氏阴性纤维杆菌-绿藻-拟杆菌超门细菌的蛋白质输出途径,是严重牙周病致病性的重要决定因素。T9SS 的核心元件是迄今为止未表征的蛋白质传导易位子,位于细菌外膜中。在这里,使用低温电子显微镜,我们提供了结构证据,证明易位子是 T9SS 蛋白 SprA。SprA 形成一个非常大的(36 链)单多肽跨膜 β-桶。桶状孔在细胞外端有盖,但有一个通向外膜表面的侧向开口。SprA 与 T9SS 不同组分结合的结构表明,伴侣蛋白控制着对侧开口和孔周质端的访问。
更新日期:2018-11-07
中文翻译:
![](https://scdn.x-mol.com/jcss/images/paperTranslation.png)
9型分泌系统结构揭示了一种新的蛋白质转运机制
9 型分泌系统 (T9SS) 是革兰氏阴性纤维杆菌-绿藻-拟杆菌超门细菌的蛋白质输出途径,是严重牙周病致病性的重要决定因素。T9SS 的核心元件是迄今为止未表征的蛋白质传导易位子,位于细菌外膜中。在这里,使用低温电子显微镜,我们提供了结构证据,证明易位子是 T9SS 蛋白 SprA。SprA 形成一个非常大的(36 链)单多肽跨膜 β-桶。桶状孔在细胞外端有盖,但有一个通向外膜表面的侧向开口。SprA 与 T9SS 不同组分结合的结构表明,伴侣蛋白控制着对侧开口和孔周质端的访问。