Structural and Functional Investigation of Tight Adhesion Locus Proteins in Bdellovibrio bacteriovorus.

乳酸菌弧菌是一种革兰氏阴性的三角洲变形杆菌和细菌捕食者，能够杀死许多革兰氏阴性的猎物，包括已知的病原体。蛭形弧菌的掠食性生命周期包括侵入宿主的质周空间分解和吸收猎物的营养物质，这使得蛭形弧菌能够有效地杀死对抗生素治疗具有耐药性的猎物物种。几项研究已经确定了蛭弧菌在卫生保健和粮食安全环境中用作抗菌剂的潜力。本项目主要研究了在IVb型菌毛组装过程中10个基因的紧密粘附（TAD）操纵子和4个基因的隐基因座。这些TAD菌毛组装蛋白的作用机制尚不清楚，以往对蛭形弧菌的研究主要集中在IVb型菌毛基因上，缺乏对TAD菌毛成分的结构研究。然而，先前的研究表明，这些毛状柱状物在HI和攻击阶段都表达，并且对猎物识别至关重要。本研究旨在对TAD和隐基因座蛋白的关键成分进行结构研究，并进行生化分析，以确定它们在菌毛组装中的功能和作用机制。提高对蛋白质在关键掠食过程中的结构和机制作用的认识是理解将蛭弧菌用作抗菌剂的关键一步。

Bdellovibrio bacteriovorus is a Gram-negative deltaproteobacterium and bacterial predator, capable of killing many Gram-negative prey species, including known pathogens. Bdellovibrio predatory lifecycle, involving invading host periplasmic space to breakdown and absorb prey nutrients, enables Bdellovibrio to efficiently kill prey species that are resistant to antibiotic treatment. Several studies have identified potential for Bdellovibrio to be used as an antimicrobial agent in healthcare and food security settings.This project focuses on a ten gene tight adherence (TAD) operon and four gene cryptic locus with hypothetical functions in the assembly of type IVb fimbriae-like pili. The mechanism of action of these TAD pilus assembly proteins remains poorly understood, with previous studies in Bdellovibrio focusing on Type IVb pilus genes and an absence of structural studies of TAD pilus components. However, previous studies have shown these fimbriae-like pilins are expressed in both HI and attack phase and are essential to prey recognition. This study aims to conduct structural investigation of key components of the TAD and cryptic loci proteins, alongside biochemical assays to determine their function and mechanism of action in pilus assembly. Improving knowledge of the structures and mechanistic role of proteins in key predatory processes is a key step in understanding use of Bdellovibrio as an antimicrobial agent.