Studies on Agrocin 84-a "Trojan Horse" tRNA synthetase inhibitor

智力上的功绩。大量的微生物次生代谢物已被证明具有抗菌特性。这些分子的生物学功能可能很复杂，反映了微生物参与的高度复杂的关系。本项目以土壤细菌辐射农杆菌K84菌株产生的细菌素--农杆菌84为研究对象。农杆菌84针对的是植物病原菌根癌农杆菌，这种细菌会导致植物中的肿瘤。农杆菌84扮演分子？特洛伊木马？通过模仿植物肿瘤衍生的底物，从而进入细胞内部，在那里它被加工成毒素TM84。TM84是亮氨酰-tRNA合成酶(Leucyl-tRNA Synthetase，LEURS)的有效抑制剂，LeURS是一种催化亮氨酸缩合为其同源tRNA的重要酶，负责正确翻译遗传密码。有趣的是，这种毒素的细菌来源是放射状农杆菌，它通过另一种合成酶AgNB2存活下来，这种合成酶对TM84具有抵抗力。本项目的目的是：确定TM84是如何抑制LURS的，并确定AgB2对TM84的抗性基础。这项研究揭示了对蛋白质翻译机制的新见解，并扩大了对微生物如何相互作用的理解。该项目的主要教育目标是增加未被充分代表的少数群体在生物化学领域的参与。这将通过让高中生和本科生及早接触生物化学科学、实验室研究经验，以及通过结合生物化学领域的讲座、研讨会和实践研究经验的项目进行指导来实现。研究生培训和辅导将整合到整个研究和教育计划中，以促进专业和科学发展。

Intellectual Merit. A vast number of microbial secondary metabolites have been shown to have antimicrobial properties. The biological functions of these molecules can be complex and reflect the highly complex relationships in which microbes engage. This project focuses on agrocin 84, a bacteriocin, produced by the soil bacterium Agrobacterium radiobacter strain K84. Agrocin 84 targets the plant pathogenic bacterium Agrobacterium tumefaciens, which induces tumors in the plant. Agrocin 84 acts a molecular ?Trojan Horse? by mimicking a plant tumor-derived substrate, and thus gaining access to the interior of the cell, where it is processed into a toxin, TM84. TM84 is a potent inhibitor of leucyl-tRNA synthetase, (LeuRS), an essential enzyme that catalyzes the condensation of a leucine to its cognate tRNA and is responsible for the correct translation of the genetic code. Interestingly, the bacterial source of the toxin, Agrobacterium radiobacter, survives by having an alternative synthetase, AgnB2, that is resistant to TM84. The aims of this project are: to determine how TM84 inhibits LeuRS and to determine the basis for AgnB2 resistance to TM84. The research has the to reveal novel insights into the protein translation machinery and to expand understanding of how microbes interact.Broader Impacts. The project has a major educational goal of increasing underrepresented minority participation in the field of biochemistry. This will be achieved by early exposure of high school and undergraduate students to the science of biochemistry, research experience in the laboratory, and mentorship through programs incorporating lectures, seminars and hands-on research experience in the field of biochemistry. Graduate student training and mentoring will be integrated throughout the research and education plans to enhance professional and scientific development.