Is inhibiting pili electrical conductivity a new anti-virulence strategy?

项目摘要 细菌与宿主细胞的黏附是感染开始的关键步骤，然而， 使细菌变得粘性的机制还没有完全了解。一长串人类病原体，包括 囊性纤维化患者肺中的铜绿假单胞菌，使用Thin(&lt；10)固定在宿主细胞上 Nm)、长(&gt；1微米)和机械强度(能够承受Pn到NN力)的长丝称为菌毛。 菌毛通过受体-配体的相互作用附着在表面，直到最近才被发现， 胞外电子转移。具有更多导电菌毛的细菌往往更具粘附性。通过 为了阐明这一观察的机械基础，我们试图建立操纵的设计规则 用于治疗目的的微生物-宿主相互作用。抑制菌毛介导的电荷转移的新疗法 可以实现阻止由致病物种形成的生物膜，或纠正 粘附性肠道微生物区系的种群。 为了实现这些可能性，我们特别致力于建立机械的相对贡献 以及菌毛介导的细菌黏附的电机制。炼金术与导向分子动力学 模拟将被用来评估菌毛的稳定性和抗拉强度作为点的函数的变化 与不同粘附性细菌相关的突变。量子力学/分子力学 实施马库斯理论，结合动力学模型，将被用来计算电学 不同菌毛的导电性。PILI将根据直接电子调制来进行突变 策略：标准残留物将被含有类似取代基的非天然残留物取代 立体但不同的电子性质。所获得的结构-功能洞察将推动第二个目标 本研究旨在合理设计和评价菌毛拮抗剂。碎片溶解的分子动力学将是 用于识别未来的结合位点，配体将在高通量筛选中对接到这些结合位点中，并且 通过自由能微扰技术进行优化。 这项工作将在耶鲁大学尼基尔·S·马尔万卡尔教授的指导下进行 在分子生物物理和生物化学系内的微生物科学研究所 与约翰·兰道夫·霍夫曼合作，化学系教授维克多·S·巴蒂斯塔。他们的 结合细菌纳米线的专业知识(马尔万卡博士)和界面的理论模型 电子转移过程(巴蒂斯塔博士)将为该项目的成功提供独特的协助。这个 奖学金培训计划包括在影响较大的期刊上发表文章，并在 生物医学和化学社区。它还包括指导研究生的机会。这个 职业发展计划包括参加职业发展办公室组织的专业发展讲习班 博士后事务，以及与该项目相关的课程。

Project Summary Adhesion of bacteria to host cells is an essential step in the initiation of an infection, and yet, the mechanisms that make bacteria sticky are not fully understood. A long list of human pathogens, including Pseudomonas aeruginosa in the lungs of cystic fibrosis patients, become anchored to host cells using thin (<10 nm), long (>1 µm), and mechanically strong (capable of withstanding pN to nN forces) filaments called pili. The pili latch onto surfaces through receptor-ligand interactions, and only very recently discovered, extracellular electron transfer. Bacteria with more electrically conductive pili tend to be more adhesive. By elucidating the mechanistic basis for this observation, we seek to establish design rules for manipulating microbe-host interactions for therapeutic purposes. New therapies that inhibit pili-mediated charge transfer could be realized to block the formation of biofilms by pathogenic species, or to correct imbalances in the populations of adhered intestinal tract microbiota. To realize these possibilities, we specifically aim to establish the relative contributions of mechanical and electrical mechanisms in bacterial adhesion mediated by pili. Alchemical and steered molecular dynamics simulations will be used to assess the change in stability and tensile strength of pili as a function of point mutations associated with differently adherent bacteria. A quantum mechanical/molecular mechanical implementation of Marcus theory, combined with a kinetic model, will be used to compute the electrical conductivity of different pili. The pili will feature mutations according to a direct electronic modulation strategy: Standard residues will be replaced with substituent-bearing unnatural counterparts that have similar steric but different electronic properties. The obtained structure-function insights will drive the second aim of our research to rationally design and evaluate pili antagonists. Fragment dissolved molecular dynamics will be used to identify prospective binding sites, into which ligands will be docked in a high throughput screen and optimized by free energy perturbation techniques. The work will be undertaken at Yale University under the mentorship of Professor Nikhil S. Malvankar of the Microbial Science Institute within the Molecular Biophysics and Biochemistry department, and in collaboration with John Randolph Huffman Professor Victor S. Batista of the Chemistry department. Their combined expertise with bacterial nanowires (Dr. Malvankar) and the theoretical modeling of interfacial electron transfer processes (Dr. Batista) will serve as unique assists for the success of the project. The fellowship training plan involves publishing in high impact journals and presenting at conferences for the biomedical and chemistry communities. It also includes the opportunity to mentor graduate students. The career development plan includes attending professional development workshops organized by the Office of Postdoctoral Affairs, as well as courses relevant to the project.