Structural and Functional Studies of Bacterial Secretion Systems

细菌分泌系统的结构和功能研究

• 批准号: RGPIN-2019-06242
• 负责人: Audette, Gerald
• 金额: $ 3.06万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714846
• 关键词: Structural; Functional; Studies; Bacterial; Secretion

Bacteria use sophisticated protein complexes to assemble structures that provide motility, adhere to multiple surfaces, and transfer DNA or proteins across membranes. Our research aims to understand, at a structural and functional level, how these protein systems assemble and interact to affect infection and virulence, increase genetic diversity, and propagate resistance strategies. One of the most versatile and complex bacterial secretion systems is the type IV secretion system (T4SS), which can be used to actively transfer DNA or proteins into and out of a cell. The process of horizontal gene transfer, also known as conjugation, of mobile plasmids is a main function of T4SSs that enables the rapid spread of advantageous genes within a bacterial population. Conjugative plasmids, such as the F plasmid of E. coli, encode genes required for T4SS assembly, pilus synthesis, plasmid transfer, and prevention of redundant plasmid transfer. Our research program is interested in understanding the regulation of F plasmid transfer between cells, and understanding how the proteins of the F plasmid T4SS interact structurally to assemble the conjugative pilus. In the current proposal, we are studying three components of the T4SS of the F plasmid: (1) the pore forming proteins TraW and TrbC; (2) the mating pair stabilization/entry exclusion proteins TraG, TraS and TraN; and (3) the T4SS coordinating protein TraH. We will determine high resolution X-ray crystal structures of these proteins, and characterize relevant protein-protein interactions. We will also explore protein dynamics using hydrogen-deuterium exchange mass spectrometry and small angle X-ray scattering. We will relate these structural observations to biological function using protein mutants and mating assays. These studies will provide a comprehensive picture of the T4SS proteins of the F plasmid, and how they functionally interact to result in DNA transfer from one bacterium to another. The long term goal of our research program is to understand the complex interactions of proteins within the T4SS assembly machinery during conjugation. This research will lead to more targeted strategies to reduce the spread of DNA through T4SS-mediated conjugation.

细菌使用复杂的蛋白质复合物来组装结构，提供运动性，粘附在多个表面，并跨膜转移DNA或蛋白质。我们的研究旨在了解，在结构和功能水平上，这些蛋白质系统如何组装和相互作用，以影响感染和毒力，增加遗传多样性，并传播抗性策略。