TRAINING

FRISBI offers a range of workshops to train graduate and post-graduate students in integrated structural biology. FRISBI courses are open to french and european researchers, from academic and industry.

ReNaFoBis together with FRISBI will organize a webinar on Thursday 12 September 2024 at 01 pm with 2 speakers:

Alicja Razew (IBS, Grenoble)

Tittle: Antibiotic Resistance: How to Monitor Drug-Protein Interactions in the Bacterial Periplasm.

Abstract: Rapid spread of antimicrobial resistance across bacterial pathogens poses a serious risk to the efficacy of available treatments. One of the promising strategies explored in the recent years concerns the use of b-lactam antibiotic together with b-lactamase inhibitor to re-sensitize antibiotic resistant, b-lactamase producers to available b-lactams. Understanding the action of these drug/inhibitor combinations is difficult due to presence of multiple competing interactions taking place in their site of action, that is periplasmic space delineated by the inner and outer membranes of Gram-negative bacteria.

In my talk, I will present our recent work describing an in-cell NMR-based research strategy to monitor the activity of the enzymes located in the periplasm. We demonstrate its unprecedented analytical power in monitoring in situ and in a real time (i) the hydrolysis of b-lactams by b-lactamases, (ii) the interaction of drugs belonging to the b-lactam family with their essential targets, and (iii) the binding of inhibitors to these enzymes. In-cell NMR that does not require purification and selective tagging of the studied enzymes, allows to evaluate the efficacy of new compounds, including drug/inhibitor combinations directly in their native environment. Therefore, this experimental strategy can be easily transferred to the investigation of new drugs or drug/inhibitor combinations targeting periplasmic proteins of antibiotic resistant pathogens.

Christina Sizun (ICSN, Gif sur Yvette)

Tittle: A dual binding mode between RSV NS1 and MED25 contributes to reshaping of antiviral responses.

Abstract: Respiratory syncytial virus (RSV), responsible for pneumonia in infants, elicits a weak innate immune response. This is partially mediated by the non-structural NS1 protein of RSV. We and others found that NS1 interacts with the MED25 subunit of the Mediator complex. NS1 binds to the MED25-ACID domain, targeted by transcription activators. This suggests that NS1 could modulate host transcription, by an unknown mechanism, as NS1 lacks a DNA binding domain. NS1 consists of a globular core domain and a C-terminal helix α3. α3 was reported to be involved in modulation of host gene expression. The α3 peptide binds to the “H2” transactivation domain (TAD)-binding face of MED25-ACID, with micromolar affinity. However, the affinity of full-length NS1 is 15 nM. Structural predictions for a heterodimer by AlphaFold2 hint at a dual binding mode, involving both TAD-binding faces of MED25-ACID, “H1” and “H2”, as well as α3 and the core domain of NS1. This rationalizes binding observed for the NS1Δα3 deletion mutant to MED25-ACID. Structural analysis of NS1 by NMR revealed significant conformational plasticity that could promote interactions with partner proteins versus self-assembly. To investigate the individual roles of NS1 subdomains, we designed mutations in the NS1 core domain. These NS1 mutants displayed significantly weaker interaction with MED25-ACID than WT NS1. Using recombinant RSV, we observed that rRSV mutants were attenuated and induced increased production of several interferon-stimulated genes, as compared to wild-type rRSV. Taken together, our results suggest that a strong interaction with MED25-ACID, achieved by cooperative binding of α3 and the core domain, is correlated to antiviral response antagonism.

Please register here: https://us06web.zoom.us/webinar/register/WN_z6OlN_U9S-S2V92TlwD8Dg

Last webinars:

June the 25th at 11 am, by Florian FAESSLER (IGBMC, Illkirch)

Title: Cryo-electron tomography of filament assemblies and their organizers

Summary: Cryo-electron tomography (cryo-ET) combined with subtomogram averaging allows structure determination in complex environments, such as cells, often recalcitrant to other structural biology approaches. While the achievable resolutions in most cases remain lower than possible with single particle analysis cryo-electron microscopy, the contextual insight provided by the tomography approach delivers a unique flavor of insights. Such insights can be crucial for understanding the architecture of filament assemblies (e.g., the actin-rich protrusions of migrating cells) and the role of their organizers. To make the best use of the structural and contextual information contained in tomograms, we assembled workflows and software pipelines that allow for rapid ultrastructural analysis of parallel and meshwork-like filament assemblies, as well as structure determination of proteins organizing such macromolecular constructions.
During this presentation, I will give a short overview of the pipelines and showcase their application, mainly in the context of actin filament networks.

May 14, 2024 Speaker: Agathe Urvoas, Institute for Integrative Biology of the Cell (I2BC),

Tittle: AlphaRep: a new platform dedicated to the selection of artificial protein binders

Summary: We have designed and assembled a large library of artificial repeat proteins named alphaRep. AlphaRep proteins binding tightly and specifically any predefined folded protein can be selected out from this library. AlphaRep generation does not require animal immunization and gives rise to renewable, sequence defined, binders. Specific alphaReps are soluble, efficiently produced, disulfide-free and extremely stable. These artificial proteins can be easily modified (fusion, dimerisation, incorporation of fluorophores, tracers, etc.) and can be used as protein tools in various contexts including Structural Biology and Cellular Biology.

The platform offers generation of alphaReps that bind with high affinity and specificity any chosen protein target. Information and contacts: https://www.i2bc.paris-saclay.fr/structural-biology/alpha-rep/

Please follow our program of ReNaFoBis-FRISBI webinars

FRISBI is involved and strongly support the French National training network in structural biology (ReNaFoBiS).  Aimed to be a national PhD training network, ReNaFoBiS coordinate and organize classes, workshops and training programs for students and post-docs.

See http://www.renafobis.fr/   for more information