Optimization of Purification and Cryo-EM Structural Determination of the Flagellar Stator MotAB-FliL Complex in Leptospira interrogans

• Grant number: 25/05589-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: February 01, 2026
• End date: January 31, 2027
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Cristiane Rodrigues Guzzo Carvalho
• Grantee: Cauê Augusto Boneto Gonçalves
• Supervisor: Albert Guskov
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Groningen, Netherlands
• Associated to the scholarship: 24/10763-6 - Structural study by electron cryomicroscopy of the MotA/MotB flagellar stator of Leptospira interrogans, BP.DD

Abstract

Leptospira interrogans is a highly motile spirochete bacterium and the causative agent of leptospirosis, a zoonotic disease with increasing global incidence. The flagellar motor of Leptospira is a complex nanomachine essential for motility and pathogenicity, driven by the interaction between rotor and stator units. The stator complex, composed of MotA, MotB, and FiIL proteins, plays a crucial role in torque generation, yet its structural and functional mechanisms remain poorly understood, particularly in spirochetes. The aim of this project is to purify and solve the high-resolution structure of the MotAB-FiIL stator complex from Leptospira interrogans using cryo-electron microscopy (cryo-EM). The small size of the complex (approximately 12-15 nm) presents a significant technical challenge. To overcome this, the project will involve optimizing membrane protein purification and cryo-EM methodologies during a research visit at the University of Groningen under the guidance of Professor Albert Guskov, an expert in membrane protein structural biology. The study will focus on elucidating the structural organization of the stator complex, particularly the role of FiIL in stabilizing MotB and enhancing torque generation. By solving the structure of this complex, the project aims to provide insights into the molecular mechanisms of flagellar motility in spirochetes, contributing to a deeper understanding of bacterial movement and pathogenicity. The findings will not only advance our knowledge of spirochete flagellar motors but also pave the way for future studies on bacterial motility and its implications for infectious diseases. (AU)