Computational and native MS studies of B-Barrel outer membrane proteins and LPS biogenesis pathways: emerging structural targets for novel antibiotics

许多致病细菌，如淋病奈瑟菌、鼠疫耶尔森菌和铜绿假单胞菌，都被称为革兰氏阴性。这意味着这些细菌被两层疏水屏障所包围，这两层屏障被称为内膜（IM）和外膜（OM），这对细菌的生存至关重要。这些膜由保护细菌免受外界环境侵害的脂质和为细胞执行许多重要任务的膜蛋白组成。膜蛋白本身具有重要的生物医学意义，因为它们占当前药物靶点的60%以上。目前迫切需要开发新的药物疗法来对抗抗生素耐药细菌的出现。该项目将研究两个主要的系统，这两个系统对维持细菌中的OM至关重要，目的是表征新药开发的结构目标。将研究的两个系统是桶装配机（或BAM复合体）和Lpt系统。BAM复合物位于OM中，并将外膜蛋白（OMPs）折叠并插入OM中，Lpt系统将脂质（LPS）运送到OM中，这对膜的生存至关重要。然而，由于膜蛋白具有强烈的两亲性（同时具有亲水性和疏水性）以及与脂质环境的动态相互作用，使用传统技术研究膜蛋白是非常具有挑战性的。因此，该项目将使用已知的天然质谱技术来维持重要的蛋白质脂质相互作用，并结合计算分子模拟来了解这些系统的动力学。该项目将能够阐明BAM复合体和Lpt系统的结构和功能，从而为未来开发新的有效抗生素。BBSRC优先领域综述：膜蛋白的研究直接针对BBSRC对抗抗生素耐药性的关键优先领域。新的和可获得的药物靶点对于对抗新出现的多重耐药细菌威胁至关重要。该项目旨在进一步表征两种关键的细菌生物发生途径；b桶组装机和Lpt系统，通过使用本地质谱和分子动力学来获得这些系统的结构和功能的重要视角。

Many disease causing bacteria such as Neisseria gonorrhoeae, Yersinia pestis, and Pseudomonas aeruginosa are known as Gram-negative. This means that these bacteria a surrounded by two hydrophobic barriers called the inner membrane (IM) and the outer membrane (OM) which are absolutely essential for the survival of the bacteria. These membranes are comprised by lipids which act to protect the bacteria against the outside environment as well as membrane proteins which perform many vital tasks for the cell. Membrane proteins themselves are of significant biomedical interest as they comprise more than 60 % of current drug targets. Currently there is an urgent need for the development of new drug therapies to fight the emergence of antibiotic resistant bacteria. This project will be studying two major systems which are vital in the maintenance of the OM in bacteria with the aim to characterise structural targets for the development of new drugs. The two systems which will be studied are the barrel assembly machine (or the BAM complex) and the Lpt system. The BAM complex resides in the OM and works to fold and insert outer membrane proteins (OMPs) into the OM, the Lpt systems shuttles a lipid known as LPS to the OM which is critical for the viability of the membrane. However, studying membrane proteins using conventional techniques is very challenging due to the strongly amphipathic nature (having both hydrophilic and hydrophobic parts) of membrane proteins as well as their dynamic interactions with their lipid environment. Therefore this project will use a native mass spectrometry technique known to maintain important protein lipid interaction in combination with computational molecular simulations to understand the dynamics of these systems. This project will be able to shed light on the structure and function of the BAM complex and the Lpt system in order to develop new and effective antibiotics for the future.Summary of BBSRC priority area:The work on membrane proteins directly targets the key BBSRC priority area of combatting antimicrobial resistance. New and accessible drug target are vital to combat the emerging threat of multidrug resistant bacteria. This project seeks to further characterise two critical bacterial biogenesis pathways; the B-barrel assembly machine and the Lpt system, by using native mass spectroscopy and molecular dynamics to gain in important sights to structure and function of these systems.