Structural and functional characterization of two potential outer membrane transporters of lignin-derived aromatic compounds

• Grant number: 24/07391-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: October 10, 2024
• End date: April 09, 2025
• Field of knowledge: Biological Sciences - Biochemistry
• Principal Investigator: Priscila Oliveira de Giuseppe
• Grantee: Damaris Batistão Martim
• Supervisor: Bert Van Den Berg
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
• Institution abroad: Newcastle University, England
• Associated to the scholarship: 23/13349-3 - Functional and structural investigation of outer membrane proteins potentially involved in the transport of lignin-related aromatic compounds, BP.PD

Abstract

The sustainable exploitation of lignin waste in producing high-value chemical compounds has gained prominence as a strategy to reduce the dependence on fossil fuel industries. In this context, microorganisms that transform the variety of compounds derived from lignin breakdown into bioproducts have been widely studied in recent decades. However, despite increasing interest in identifying enzymes involved in the bioconversion of ligninþderived aromatic compounds within microbial cells, there is still a limited understanding of how these compounds enter the cells, particularly regarding the function of transporters in both the inner and outer membranes. In a previous study, we identified two putative ²-barrel-type outer membrane (OM) proteins (XAC0352 and XAC0876), belonging to the COG4313 family, as potentially involved in transporting lignin-derived aromatics in Xanthomonas citri subsp. citri 306. To date, only one member of this transporter family has had its structure elucidated, while two have had their functions identified. However, none have been demonstrated to play a role in the transport of lignin-derived aromatic compounds. In the ongoing Postdoc project (FAPESP 2023/13349-3), our major aim is to test the hypothesis that these OM proteins play a role in the uptake of lignin-related compounds. Within this context, the main goal of the present BEPE project is to investigate the molecular mechanisms that determine their functions. For this purpose, our approach includes protein crystallography and functional in vitro assays. Since heterologous expression, purification, characterization and crystallization of (outer) membrane proteins pose significant challenges, we propose a collaboration with Prof. Bert van den Berg from Newcastle University (UK), who is one of the leading experts in the structural biology of OM proteins, and whose team has already solved more than 100 crystallographic structures of OM proteins. This BEPE proposal not only addresses anscientific challenge but also provides a valuable learning opportunity, expanding our group's expertise regarding structure-function studies of proteins, that so far have been limited to those that are soluble in water.