Functional and structural investigation of outer membrane proteins potentially involved in the transport of lignin-related aromatic compounds

• Grant number: 23/13349-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2024
• End date: August 31, 2026
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Priscila Oliveira de Giuseppe
• Grantee: Damaris Batistão Martim
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
• Associated scholarship(s): 24/07391-0 - Structural and functional characterization of two potential outer membrane transporters of lignin-derived aromatic compounds, BE.EP.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 industries. In this context, the use of microorganisms to funnel the variety of compounds resulting from the initial depolymerization of lignin into bioproducts, formed in convergence points of the central carbon metabolism, has been widely explored in recent decades. However, despite the growing interest in identifying the enzymes and enzymatic mechanisms involved in the bioconversion of lignin derivatives, understanding how cells uptake these compounds, including the function of transporters in the outer membrane, remains limited. In a previous study aimed at identifying metabolic pathways for the metabolism of lignin-related compounds in Xanthomonas citri subsp. citri 306, two outer membrane ²-barrel-type transporters belonging to the COG4313 family were identified as potentially involved in the transport of lignin-related aromatics. 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 related to the transport of lignin-derived aromatic compounds. Therefore, our main goal is to elucidate the in vivo role of two ²-barrel-type outer membrane transporters in the metabolism of lignin-derived aromatic compounds and uncover the molecular mechanisms that determine their functions. To achieve this goal, our strategy encompasses a multidisciplinary approach that includes genetic engineering, analytical chemistry, fluorescence microscopy, and protein crystallography. Our greatest challenge will be these transporters' heterologous expression, purification, and crystallization. For this purpose, we will collaborate with Prof. Bert van den Berg from the University of Newcastle, one of the leading experts in the structural biology of membrane transporters, whose team has already solved more than 100 crystallographic structures of outer membrane proteins.