Chemical and Biological Studies of the Guadinomines

描述（由申请人提供）：该奖学金有三个目标。第一个目的是通过组合的合成和生物合成方法来使用胍胺的创建类似物。将合成假设驱动的类似物，每一个都解决了一个问题，即哪些结构特征是III型分泌系统（TTSS）抑制所必需的。还将制备类似物，其应充当用于靶向生物合成的底物，其应允许胍基丁胺类似物的快速形成。 第二个目的是设计一种改进的胍基丁胺的分离方案。天然胍胺A和B以约1 mg/L培养基的水平存在，并且需要繁琐的纯化程序。由于胍胺A和B都含有一个邻位二胺，一个不常见的结构亚基，我们将利用其反应性，以提高其分离。我们已经表明，二胺与含氟醛在室温下干净地反应，无需添加催化剂即可制备缩醛胺（May，Khosla -未发表的结果）。这将允许从培养基中的剩余材料中进行固相氟提取。 第三个目的是确定胍丁胺的TTSS抑制范围，并确定它们如何影响其靶标。我们已经表明植物病原体黄单胞菌被胍基丁胺A抑制（May，Mudgett -未发表的结果），并且将继续用天然胍基丁胺及其类似物研究植物病原体。我们将使用小肠炎耶尔森氏菌检测，以确定哪些效应蛋白，结构蛋白和伴侣蛋白受到胍丁胺的影响。这些知识将使新的和更有效的类似物的第二代设计成为可能。 公共卫生相关性：致病性革兰氏阴性菌使用III型分泌系统（TTSS）感染宿主。该提案的目标是研究胍胺如何抑制TTSS，并制备新的更有效的类似物。

DESCRIPTION (provided by applicant): This fellowship has three Aims. The first Aim is to use the create analogs of the guadinomines through a combined synthetic and biosynthetic approach. Hypothesis-driven analogs will be synthesized, each addressing a question about which structural features are necessary for Type III Secretion System (TTSS) inhibition. Analogs will also be made that should serve as substrates for precursor-directed biosynthesis, which should allow the rapid formation of guadinomine analogs. The second Aim is to devise an improved isolation protocol for guadinomines. Natural guadinomines A and B are present at levels of ~1 mg/L of culture media, and require tedious purification procedures. Since guadinomines A and B both contain a vicinal diamine, an uncommon structural subunit, we will exploit its reactivity to enhance its isolation. We have shown that diamines react cleanly with fluorine-containing aldehydes to make aminals at room temperature without added catalysts (May, Khosla - unpublished results). This will allow for solid phase fluorous extraction from the remaining material in the culture media. The third Aim is to determine the scope of TTSS inhibition of the guadinomines, and determine how they affect their targets. We have shown that the plant pathogen Xanthomonas is inhibited by guadinomine A (May, Mudgett - unpublished results) and will continue to study plant pathogens with natural guadinomines and their analogs. We will use a Yersinia enterolitica assay to determine which effector proteins, structural proteins, and chaperones are affected by guadinomines. This knowledge will enable a second-generation design of new and more potent analogs. PUBLIC HEALTH RELEVANCE: Pathogenic Gram-negative bacteria use a Type III Secretion System (TTSS) to infect hosts. The goals of the proposal are to study how the guadinomines inhibit TTSS, and to make new and more potent analogs.