Biochemical and Structural Characterization of the Unique Membrane Complex in the Type VI Secretion System of Bacteroidota
Event details
| Date | 11.12.2024 |
| Hour | 14:30 › 15:30 |
| Speaker | Thibault Bongiovanni, Laboratoire de Chimie Bactérienne (LCB), Centre National de la Recherche Scientifique (CNRS), Marseille (FR) |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
BIOENGINEERING SEMINAR
Abstract:
The type VI secretion system (T6SS) of Gram-negative bacteria inhibits competitor cells through contact-dependent translocation of toxic effector proteins. In Proteobacteria, the T6SS is anchored to the cell envelope through a megadalton-sized membrane complex (MC). However, the genomes of Bacteroidota with T6SSs appear to lack genes encoding homologs of canonical MCcomponents.Here, we identify five genes in Bacteroides fragilis (tssNQOPR) that are essential for T6SS function and encode a Bacteroidota-specificMC. We purify this complex, reveal its dimensions using electron microscopy, and identify a protein-protein interaction network underlying the assembly of the MC including the stoichiometry of the five TssNQOPR components. Protein TssN mediates the connection between the Bacteroidota MC and the conserved baseplate. Although MC gene content and organization varies across the phylum Bacteroidota, no MC homologs are detected outside of T6SS loci, suggesting ancient co-option and functional convergence with the nonhomologous MC of Pseudomonadota.
Bio:
During his PhD at the LISM and LCB laboratories in Marseille, France, Thibault Bongiovanni delved into the intricate world of large membrane protein complexes. His research focused on elucidating the molecular mechanisms underlying their assembly and integration into bacterial membranes. He employed a multidisciplinary approach, combining biochemical, computational, biophysical, and structural biology techniques, including cryo-electron microscopy. Through these investigations, he gained a deeper understanding of the assembly of large macromolecular complexes and their membrane insertion.
Zoom link for attending remotely: https://epfl.zoom.us/j/65780945453
Abstract:
The type VI secretion system (T6SS) of Gram-negative bacteria inhibits competitor cells through contact-dependent translocation of toxic effector proteins. In Proteobacteria, the T6SS is anchored to the cell envelope through a megadalton-sized membrane complex (MC). However, the genomes of Bacteroidota with T6SSs appear to lack genes encoding homologs of canonical MCcomponents.Here, we identify five genes in Bacteroides fragilis (tssNQOPR) that are essential for T6SS function and encode a Bacteroidota-specificMC. We purify this complex, reveal its dimensions using electron microscopy, and identify a protein-protein interaction network underlying the assembly of the MC including the stoichiometry of the five TssNQOPR components. Protein TssN mediates the connection between the Bacteroidota MC and the conserved baseplate. Although MC gene content and organization varies across the phylum Bacteroidota, no MC homologs are detected outside of T6SS loci, suggesting ancient co-option and functional convergence with the nonhomologous MC of Pseudomonadota.
Bio:
During his PhD at the LISM and LCB laboratories in Marseille, France, Thibault Bongiovanni delved into the intricate world of large membrane protein complexes. His research focused on elucidating the molecular mechanisms underlying their assembly and integration into bacterial membranes. He employed a multidisciplinary approach, combining biochemical, computational, biophysical, and structural biology techniques, including cryo-electron microscopy. Through these investigations, he gained a deeper understanding of the assembly of large macromolecular complexes and their membrane insertion.
Zoom link for attending remotely: https://epfl.zoom.us/j/65780945453
Practical information
- Informed public
- Free
Organizer
- Prof. Bruno Correia, Laboratory of Protein Design and Immunoengineering (LPDI), Institute of Bioengineering (IBI), École Polytechnique Fédérale de Lausanne (EPFL)
Contact
- Ms. Suzanne Balharry, Laboratory of Protein Design and Immunoengineering (LPDI), Institute of Bioengineering (IBI), École polytechnique fédérale de Lausanne (EPFL)