Biosynthesis and secretion of bacterial siderophores

细菌铁载体的生物合成和分泌

• 批准号: 341983-2007
• 负责人: Pawalek, Peter
• 金额: $ 2.91万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=429976
• 关键词: Biosynthesis; secretion; bacterial; siderophores

Protein-protein interactions have been shown to be essential for a number of cellular processes including respiration. If we can find out how to stop bacteria from growing in iron-limited conditions by disrupting protein-protein interactions, we may eventually be able to use this information to discover powerful new antibiotics to which bacteria do not have resistance. Ferric iron is an essential nutrient for most bacteria, but this element is very scarce in the extracellular environment. To obtain scarce yet essential iron, bacteria have developed an iron acquisition strategy that relies on molecules called siderophores. Bacteria synthesize siderophores in the cytoplasm and then secrete them in order to scavenge iron from their environment. To get ferric-siderophores back into the cell, Gram-negative bacteria rely on a network of proteins in the cell envelope to import ferric-siderophores so they can be used for metabolic processes. Although we now know quite a bit about how the proteins in the import network work together to bring ferric-siderophores into the bacterial cell, we still know very little about how proteins work together to make siderophores and secrete them out of the cell. We will characterize the proteins involved in the synthesis and secretion of the E. coli siderophore called enterobactin. By understanding how these proteins work together, we will gain fundamental knowledge that will help us to understand how pathogenic bacteria use siderophores as virulence factors to cause diseases in animals and plants. We want to know if the enterobactin synthesis and secretion proteins communicate with each other through a network of protein-protein interactions, similar to what has already been shown for the proteins involved in ferric-siderophore import. We will try to find out if and how these proteins interact in our controlled laboratory environment by using biophysical techniques. We will also try to solve the three-dimensional structures of these proteins so that we can learn more about the protein surfaces that may tell us how they fit together. Once we know how these proteins can fit together based on our laboratory techniques, we can introduce mutations into these proteins to try to disrupt their interactions in a cell.

蛋白质之间的相互作用已被证明对包括呼吸在内的许多细胞过程至关重要。如果我们能找到如何通过破坏蛋白质之间的相互作用来阻止细菌在铁限制条件下生长的方法，我们可能最终能够利用这一信息来发现细菌没有抗药性的强大的新抗生素。铁是大多数细菌必需的营养物质，但这种元素在细胞外环境中非常稀缺。为了获得稀缺但必需的铁，细菌已经开发出一种依赖于称为铁载体的分子的铁获取策略。细菌在细胞质中合成铁载体，然后分泌铁载体，从环境中清除铁。为了让铁-铁载体回到细胞中，革兰氏阴性细菌依靠细胞包膜中的蛋白质网络来进口铁-铁载体，这样它们就可以用于代谢过程。尽管我们现在对输入网络中的蛋白质如何协同作用将铁-铁载体带入细菌细胞已经有了相当多的了解，但对于蛋白质如何协同作用制造铁载体并将它们分泌出细胞，我们仍然知之甚少。我们将描述参与大肠杆菌铁载体肠杆菌蛋白的合成和分泌的蛋白质。通过了解这些蛋白质如何协同工作，我们将获得基础知识，这将有助于我们了解致病菌如何利用铁载体作为毒力因子在动物和植物中引起疾病。我们想知道肠杆菌蛋白的合成和分泌蛋白是否通过蛋白质-蛋白质相互作用的网络相互沟通，类似于已经显示的参与铁-铁载体进口的蛋白质。我们将尝试通过使用生物物理技术来找出这些蛋白质是否以及如何在我们控制的实验室环境中相互作用。我们还将尝试解决这些蛋白质的三维结构，这样我们就可以更多地了解蛋白质表面，从而告诉我们它们是如何组合在一起的。一旦我们根据实验室技术知道了这些蛋白质是如何结合在一起的，我们就可以在这些蛋白质中引入突变，试图破坏它们在细胞中的相互作用。