Monday, December 5

14:00 am

@ IECB auditorium

Dr. Sébastien GOEB

Laboratory MOLTECH-Anjou, Angers University

Stimuli responsive coordination cages

Coordination driven self-assembly has allowed the preparation of many molecular polygons and polyhedrons with remarkable properties. They are obtained by association of polytopic ligands and complexes showing a pre-organized geometry. The corresponding host cavities offer promising opportunities for applications in molecular recognition or even in guest transport. We focused our attention for several years in the design of electro-active self-assembled 2D and 3D discrete structures based on the tetrathiafulvalene unit (TTF) and derivatives (exTTF and DTF for example) with the aim of controlling the guest release thanks to an electrochemical stimulus. We are also interested in understanding the key parameters governing the formation of an emergent class of coordination assemblies, i.e. interlocked cages. We believe that such compact objects could offer promising opportunities in controlling the structural organization of donor and acceptor units. For example, we demonstrated recently that truxene based ligands, associated with dinuclear Ruthenium or Rhodium complexes, can produce this type of compact interlocked systems.

Host: Yann FERRAND

Thursday, December 8

11:15 am

@ IECB auditorium

Dr. Ana S. Ramirez

Institute of Molecular Biology and Biophysics, ETH Zurich

Structural and mechanistic insight into protein N-glycosylation

Protein N-glycosylation is a post-translational modification that exists in all domains of life. It consists of two main steps: (1) biosynthesis of a lipid-linked oligosaccharide (LLO), and (2) the glycan transfer from LLO to asparagine residues of acceptor proteins, a process catalyzed by oligosaccharyltransferase (OST) enzymes. N-glycosylation plays essential roles in several cellular processes, such as protein folding, function, and cell-cell communication. During the last years, my research has focused on the structural and mechanistic investigation of N-glycosylation enzymes in bacteria, humans, yeast, and protozoan parasites using a multidisciplinary approach that involves protein biochemistry, chemo-enzymatic glycan elongation, X-ray crystallography, and single-particle Cryo-EM. We described a counting mechanism for PglH, a processive glycosyltransferase involved in LLO biosynthesis in the bacterial human pathogen Campylobacter jejuni [1]. In higher eukaryotes, where OST enzymes are multimeric membrane complexes located at the membrane of the endoplasmic reticulum (ER), we determined cryo-EM structures of the two OST enzymes that co-exist in human cells, revealing the molecular basis of their specific function in catalyzing co-translational or post-translational N-glycosylation [2]. Recently, we elucidated cryo-EM structures of the yeast multimeric OST complex in different functional states revealing the molecular basis of substrate recognition and catalysis [3].

1. Ramírez, A. S. et al. Structural basis of the molecular ruler mechanism of a bacterial glycosyltransferase. Nat. Commun. 9, 445 (2018).

2. Ramírez, A. S., Kowal, J. & Locher, K. P. Cryo-electron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B. Science 366, 1372–1375 (2019).

3. Ramírez, A. S. et al. Molecular basis for glycan recognition and reaction priming of eukaryotic oligosaccharyltransferase. Nat. Commun. 13, 7296 (2022).

Host: Nicolas REYES

IECB Friday seminars 2022

November 10, 2022:

Prof. Ruchi Anand (Indian Institute of Technology Bombay)

Title: Strategies to Combat Antibiotic Resistance

November 4, 2022:

Dr. Gabriela Balíková Novotná (Institute of Microbiology of the Czech Academy of Sciences)

Title: ANTIBIOTIC RESISTANCE OR SIGNALING? The role of ABCF ATPases in antibiotic producers

October 7, 2022:

Dr. Chrystel Lopin-Bon (Institut de Chimie Organique et Analytique, Université d’Orléans)

Title: Synthesis of Chondroitin Sulfate (CS) oligosaccharides as tools to decipher proteins-CS interaction

Dr. Vincent Ferrières (Institut des Sciences Chimiques de Rennes, ENSCR, Université de Rennes 1)

Title: Rare lichenic carbohydrates and advanced mass spectrometry

Dr. Carmen Galan (School of Chemistry, University of Bristol, UK)

Title: Novel catalytic methods for the stereoselective synthesis of deoxyglycosides as diagnostic tools

September 23, 2022:

Dr. Emilie Moulin (Institut Charles Sadron (ICS), Strasbourg)

Title: Contractile Materials from Molecular Machines

Dr. Julien Leclaire (Université Claude Bernard Lyon 1, Lyon)

Title: Dynamic covalent chemistry at work: from the propagation of molecular information to the concomitant recycling of CO2 and metals from waste material

July 4, 2022:

Dr. Tomohisa Sawada (Tokyo Institute of Technology, Japan)

Title: Metal–peptide rings and nets with entangling topologies

June 10, 2022:

Dr. Leos Valasek (Institute of Microbiology of the Czech Academy of Sciences, Czech Republic)

Title: Longer is not always the best; lessons from the tRNA anticodon stem

March 31, 2022:

Dr. Fabienne Burlina (Laboratoire des Biomolécules, Sorbonne Université, Paris)

Title: Extending chemical ligation for the synthesis of proteins: application to NEMO ubiquitylation

Dr. Yung-Sing Wong (Département de pharmacologie moléculaire, Equipe Chémobiologie et outils moléculaires thérapeutiques, Université Grenoble-Alpes, Grenoble)

Title: Benefits of forming spatio-temporal chemical bonds in living environments

March 18, 2022:

Dr. Kevin Macé (Birkbeck college, Institute of Structural and Molecular Biology, UK)

Title: Type 4 secretion system cryo-EM structures

IECB Friday seminars 2021

January 12, 2021:

Dr. Hervé Vezin (CNRS - Laboratoire Avancé de Spectroscopie pour les Interactions la Réactivité et l'Environnement (LASIRE), Université de Lille)

Title: Advanced EPR spectroscopy in material chemistry for batteries

February 5, 2021:

Dr. Hagen Hofmann (Department of Structural Biology, Weizmann Institute of Science)

Title: Allostery through DNA drives phenotype switching

March 5, 2021:

Prof. Camilo Perez (Biozentrum, University of Basel)

Title: Structure and mechanism of a proton dependent lipid transporter involved in lipoteichoic-acids biosynthesis

March 18, 2021:

Dr. Michael Eck (Dana-Farber Cancer Institute and Harvard Medical School)

Title: Insights into regulation of the Ras/Raf/MAPk pathway from Cryo-EM Structures of BRAF-MEK-14-3-3 Complexes

March 26, 2021:

Dr. Stephan Rauschenbach (University of Oxford)

Title: Electrospray ion beam deposition for single molecule imaging

April 2, 2021:

Prof. Bernard Rentier (Recteur Honoraire, Université de Liège)

Title: Open Science: Excellence revisited

April 15, 2021:

Dr. Nora Vazquez-Laslop (University of Illinois at Chicago)

Title: Macrolide antibiotics as modulators of translation

May 7, 2021:

Dr. Abhishek Chatterjee (Department of Chemistry, Boston College)

Title: Genetically encoded chemistries to read and write biology

May 28, 2021:

Dr. Julien Gronnier (Center for Plant Molecular Biology, University of Tübingen)

Title: Nanoscale regulation of cell-surface receptor signaling

June 3, 2021:

Dr. Jonathan Visentin (CHU de Bordeaux, Université de Bordeaux, Immuno ConcEpT, UMR CNRS 5164)

Title: Surface plasmon resonance to study anti-HLA antibodies: transfer of a basic science method to the bedside of organ transplant recipients and beyond

June 11, 2021:

Prof. Pierre Sonveaux & Prof. Raphaël Frédérick (Université catholique de Louvain)

Title: Discovery of an oxidative pathway of lactate in cancer and its druggability by inhibitors of lactate dehydrogenase 1 (LDH1) oligomerization

June 11, 2021:

Dr. Alexander Harms (Biozentrum, University of Basel)

Title: Drop out or go viral: A story of planned and unplanned expeditions into the phage world

June 25, 2021:

Dr. Eric Cornes (Institute Pasteur)

Title: Non-coding small RNAs as versatile regulators of germline gene expression programs

June 25, 2021:

Dr. Jacob Bobonis (EMBL Heidelberg)

Title: Bacterial retrons encode phage-sensing toxin/antitoxin systems

September 13, 2021:

Dr. Benoit Malleret (National University of Singapore)

Title: Molecular mechanisms of Plasmodium vivax invasion and cell tropism of zoonotic malaria species

September 22, 2021:

Prof. Valérie de Crécy-Lagard (University of Florida)

Title: Linking gene and function by comparative genomics: examples from deazapurine metabolism reveal cross-talks between RNA and DNA modifications

October 29, 2021:

Dr. Vishukumar Aimanianda (Institut Pasteur)

Title: Fungal cell-wall polysaccharides, exploiting their translational potential

November 26, 2021:

Dr. Niels Fischer (Max Planck Institute for Biophysical Chemistry, Germany)

Title: Single particle cryo-EM - Towards atomic-resolution of molecular machines in motion

Dr. Megan Wright (University of Leeds, UK)

Title: Chemical proteomic tools to study host-microbe interactions