Breaking the Barrier: Mapping protein interactions in the bacterial outer membrane as targets for new antimicrobials

打破障碍：绘制细菌外膜中的蛋白质相互作用作为新抗菌药物的目标

• 批准号: MR/Y012453/1
• 负责人: Neil Ranson
• 金额: $ 279.56万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FY012453%2F1
• 关键词: Breaking; Barrier; Mapping; protein; interactions

Across human history, bacteria have been responsible for a huge burden of disease and mortality that only lessened with the discovery of vaccination and antibiotics. We now face a rising tide of antimicrobial resistance, and are experiencing a slow-moving pandemic of hospital-acquired infections by drug-resistant bacteria. Alongside better prevention, control, and surveillance, there is an urgent need to identify new targets against which we can develop new antibiotic drugs. Of particular concern are the Gram-negative group of bacteria. Of the five microorganisms identified as urgent threats by the US Centres for Disease Control, three are Gram-negative bacteria, and while there are worryingly few new antibiotics in trials, even fewer target Gram-negative bacteria. Membranes, and the proteins associated with them, constitute the majority of current drug targets across multiple disease areas, largely because membranes are the basis for much compartmentalisation and communication in and between cells. Gram-negative bacteria have a unique, additional, protective outer membrane (OM) that shields the bacterium from its environment. The OM is a major barrier to toxins and antibiotics, and is critical for bacterial growth, virulence, pathogenesis, and the formation of biofilms (which are important for establishing many infections). All biological membranes have two leaflets of amphipathic lipid molecules (typically phospholipids) that form a bilayer, and the lipids in each leaflet are different (asymmetric). The bacterial OM is perhaps the most striking example of membrane asymmetry in biology, with an inner leaflet dominated by phospholipids (as in normal membranes), and an outer leaflet dominated by lipopolysaccharide molecules (which are unique to the bacterial membrane). Integral outer membrane proteins (OMPs), which all have a barrel-shaped structure, have thus evolved to fold and function in a different environment to proteins in other membranes: they experience a very rigid membrane because the lipopolysaccharide clumps together. Furthermore, they don't move around very much in the membrane, and their conformations and interactions are dictated by interactions with other proteins and lipopolysaccharide that are missing in other membranes, but essential for bacterial growth and survival. The OM is thus a fascinating environment that could provide a rich source of new targets for antibacterial interventions. In this MRC programme grant, we will integrate functional and structural studies on the bacterial OM, with the latest innovations in protein structure (and protein interaction) prediction, and in our ability to design new proteins that can bind target proteins. Working in the test tube and with whole bacterial cells, we will learn how OMPs naturally fold up and become embedded within the outer membrane, how they interact with each other and with LPS molecules when they're in that membrane, and how these interactions affect the ways proteins work and how bacteria grow. Ultimately, we want to use these discoveries to illuminate new ways of killing bacteria, or at least weakening their defences so that other drugs can kill them. A programme grant is essential because it will allow us to build a talented team that can work together to make discoveries at a pace and scale that would be impossible via individual, smaller project grants, and it will allow us to place the UK at the forefront of this vital area of research.

纵观人类历史，细菌造成了巨大的疾病和死亡负担，而随着疫苗接种和抗生素的发现，这种负担才得以减轻。我们现在面临着不断上升的抗菌药物耐药性浪潮，并且正在经历耐药细菌医院获得性感染的缓慢流行。除了更好的预防、控制和监测外，还迫切需要确定新的靶标，以开发新的抗生素药物。特别值得关注的是革兰氏阴性细菌。在美国疾病控制中心确定为紧急威胁的五种微生物中，有三种是革兰氏阴性菌，尽管处于试验阶段的新抗生素少得令人担忧，但针对革兰氏阴性菌的抗生素就更少了。膜以及与其相关的蛋白质构成了当前多个疾病领域的大部分药物靶点，这主要是因为膜是细胞内和细胞间许多区隔和通讯的基础。革兰氏阴性细菌具有独特的附加保护性外膜 (OM)，可以保护细菌免受环境影响。 OM 是毒素和抗生素的主要屏障，对于细菌生长、毒力、发病机制和生物膜的形成（这对于建立许多感染很重要）至关重要。所有生物膜都有两个形成双层的两亲性脂质分子（通常是磷脂）小叶，并且每个小叶中的脂质是不同的（不对称）。细菌 OM 可能是生物学中膜不对称性最引人注目的例子，其内部小叶以磷脂为主（如正常膜），而外部小叶以脂多糖分子为主（这是细菌膜所特有的）。整体外膜蛋白（OMP）都具有桶状结构，因此进化为在与其他膜中的蛋白质不同的环境中折叠和发挥作用：它们经历了非常坚硬的膜，因为脂多糖聚集在一起。此外，它们在膜中移动不多，它们的构象和相互作用是由与其他蛋白质和脂多糖的相互作用决定的，这些蛋白质和脂多糖在其他膜中缺失，但对于细菌的生长和生存至关重要。因此，OM 是一个令人着迷的环境，可以为抗菌干预提供丰富的新靶点。在这项 MRC 计划拨款中，我们将整合细菌 OM 的功能和结构研究、蛋白质结构（和蛋白质相互作用）预测的最新创新，以及设计能够结合目标蛋白质的新蛋白质的能力。在试管和整个细菌细胞中工作，我们将了解 OMP 如何自然折叠并嵌入外膜内，它们在外膜中如何彼此相互作用以及与 LPS 分子相互作用，以及这些相互作用如何影响蛋白质的工作方式和细菌的生长方式。最终，我们希望利用这些发现来阐明杀死细菌的新方法，或者至少削弱它们的防御能力，以便其他药物可以杀死它们。项目拨款至关重要，因为它将使我们能够建立一支才华横溢的团队，能够共同努力，以通过个人较小的项目拨款不可能实现的速度和规模进行发现，并使我们能够将英国置于最前沿这个重要的研究领域。