| Grant number: | 22/08730-7 |
| Support Opportunities: | Regular Research Grants |
| Start date: | May 01, 2023 |
| End date: | October 31, 2025 |
| Field of knowledge: | Biological Sciences - Biochemistry - Chemistry of Macromolecules |
| Principal Investigator: | Cristiane Rodrigues Guzzo Carvalho |
| Grantee: | Cristiane Rodrigues Guzzo Carvalho |
| Host Institution: | Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
| City of the host institution: | São Paulo |
| Associated researchers: | Robson Francisco de Souza |
Abstract
In this work, we will be working with two bacteria: the plant pathogen Xanthomonas citri (X. citri) and the human pathogen Leptospira interrogans (Lic). X. citri causes citrus canker in citrus crops, causing significant damage to Brazilian agriculture. It is a bacterium that uses an extracellular appendage, the type IV pilus (T4P), to move around (twitching). This filament is assembled through a protein nanomachine that crosses the bacterial wall, and some bacteriophages, such as ¦Xacm4-11, take advantage of these extracellular structures to infect X. citri. We obtained structural data on the T4P secretin, PilQ, which was co-purified with the TsaP protein. In this regular project, we intend to refine this structure and understand the role of TsaP in T4P function. In addition, our group was able to purify the isolated T4P filament and in complex with ¦Xacm4-11But the complex is not stable, and we need to optimize the purification conditions. Cryo-EM data collection of the filament has been obtained, and we are trying to solve its helical structure. Our research group has shown that X. citri produces outer membrane vesicles (OMVs), and we are investigating their composition and biological role (see manuscript on BioRxiv: https://doi.org/10.1101/2021.04.26.441564).Leptospirosis is an infectious disease caused by species of the bacterial genus Leptospira and is more common in tropical areas with poor sanitation. In Brazil, it is endemic and causes about 1,000 deaths per year. The disease can range from asymptomatic to severe and has a significant impact on the economy, emphasizing the importance of studying the biology and pathogenesis of this neglected pathogen. Our goal is to study the signaling network involving the second messenger c-di-GMP, with a focus on refining the structure of the diguanylate cyclase LIC_11128, which binds to brevianamide F. We do not yet know the effect of this natural compound on the enzymatic activity of LIC_11128 and on the survival of the bacterium. In addition, we will finalize our functional studies of the possible virulence factor LIC_11568, located in the T2SS cluster. Our studies have the potential to provide important information about the biology and pathogenesis of these bacteria, contributing to the understanding and control of diseases that affect agriculture and human health. (AU)
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