小柯机器人

四川大学董浩浩等研究人员合作揭示BAM介导的外膜β-桶状蛋白组装的结构基础。这一研究成果于2023年4月26日在线发表在国际学术期刊《自然》上。

据研究人员介绍，外膜结构在革兰氏阴性菌、线粒体和叶绿体中很常见，包含外膜β桶蛋白（OMP），是物质交换的重要门户。所有已知的OMP都有反平行的β链拓扑结构，这意味着有共同的演化起源和保守的折叠机制。人们已经提出了细菌β-桶装配机器（BAM）启动OMP折叠的模型；然而，BAM着手完成OMP装配的机制仍不清楚。

研究人员报告了BAM组装OMP底物EspP的中间结构，病证明了BAM在OMP组装的后期阶段的连续构象动力学，这得到了分子动力学模拟的进一步支持。体外诱变和体内组装试验揭示了BamA和EspP的功能性残基，用于桶杂交、封闭和释放。这项工作对OMP组装的共同机制提供了新的见解。

附：英文原文

Title: Structural basis of BAM-mediated outer membrane β-barrel protein assembly

Author: Shen, Chongrong, Chang, Shenghai, Luo, Qinghua, Chan, Kevin Chun, Zhang, Zhibo, Luo, Bingnan, Xie, Teng, Lu, Guangwen, Zhu, Xiaofeng, Wei, Xiawei, Dong, Changjiang, Zhou, Ruhong, Zhang, Xing, Tang, Xiaodi, Dong, Haohao

Issue&Volume: 2023-04-26

Abstract: The outer membrane structure is common in Gram-negative bacteria, mitochondria and chloroplasts, and contains outer membrane β-barrel proteins (OMPs) that are essential interchange portals of materials1,2,3. All known OMPs share the antiparallel β-strand topology4, implicating a common evolutionary origin and conserved folding mechanism. Models have been proposed for bacterial β-barrel assembly machinery (BAM) to initiate OMP folding5,6; however, mechanisms by which BAM proceeds to complete OMP assembly remain unclear. Here we report intermediate structures of BAM assembling an OMP substrate, EspP, demonstrating sequential conformational dynamics of BAM during the late stages of OMP assembly, which is further supported by molecular dynamics simulations. Mutagenic in vitro and in vivo assembly assays reveal functional residues of BamA and EspP for barrel hybridization, closure and release. Our work provides novel insights into the common mechanism of OMP assembly.

DOI: 10.1038/s41586-023-05988-8

Source: https://www.nature.com/articles/s41586-023-05988-8

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html