Unravelling the rules of outer membrane protein folding: Opportunities for the design of new antibacterial strategies

外膜蛋白(OMP)的折叠和组装是构建革兰氏阴性细菌细胞壁的关键。OMP的序列如何使它们能够折叠到细菌OM中仍是未知的，也不知道基本的B桶组装机械(BAM)如何识别折叠OMP并将它们插入到外膜(OM)中。了解OMP折叠不仅具有巨大的基础兴趣，而且在翻译上也很重要，因为针对这一途径可能会导致对抗革兰氏阴性病原体抗生素耐药性的新策略。在最近与David Baker(西雅图)(Science 2021)合作的基础上，我们成功地设计了第一个合成的跨膜β桶蛋白，提供了一个独特的机会来比较从头设计的蛋白质与其自然进化的体外蛋白质的折叠机制，并在BAM的协助/不协助下。这个项目将决定：(I)OMPS序列如何在体外有效地折叠成其高度稳定的β桶结构；(Ii)OMPS的哪些序列/结构基序被BAM识别；(Iii)细胞机制如何识别OMPS并将它们靶向BAM以折叠成OM。这些结果将是关于OMP折叠的新的基础知识，对BAM如何识别OMP的新的见解，以及潜在的通过靶向OMP折叠来对抗抗生素耐药性的新途径。

The folding and assembly of outer membrane proteins (OMPs) is essential to build the cell wall of gram-negative bacteria. How the sequences of OMPs enable their folding into the bacterial OM remains unknown, nor is it understood how the essential B-barrel assembly machinery (BAM), recognises folding OMPs and inserts them into the outer membrane (OM). Understanding OMP folding is not only of immense fundamental interest, but is translationally important as targeting this pathway could lead to new strategies to combat antibiotic resistance in gram-negative pathogens. Building on a recent collaboration with David Baker (Seattle) (Science 2021), we have successfully designed the first synthetic trans membrane beta barrel protein, providing a unique opportunity to compare the folding mechanisms of de novo designed proteins with their naturally evolved counterparts in vitro, and assisted/unassisted by BAM.This project will determine:(i) how the sequence of OMPs enables efficient folding to their highly-stable beta-barrel structures in vitro; (ii) which sequence/structural motifs of OMPs are recognised by BAM;(iii) how the cellular machinery recognizes OMPS and targets them to BAM for folding into the OM. The results will be new fundamental knowledge of how OMPs fold, new insights into how BAM recognises OMPs and potentially, new routs of combat antibiotic resistance by targeting OMP folding.