2023

Photoconvertible fluorescent proteins (PCFPs) such as mEos4b change their fluorescence color from green to red upon illumination with UV light. They are popular markers for super-resolution imaging modalities such as quantitative and single particle tracking Single Molecule Localization Microscopy (SMLM). The photophysical properties of these proteins, however, are exceedingly complex. In this collaborative work involving the NMR and I2SR groups of the IBS, researchers observed by (…)

Since 2022, the Fondation Bettencourt Schueller has launched a new program to support great talents in life sciences research: Impulscience®. Each year, Impulscience awards seven grants and IBS is proud to count two recipients among its researchers: Malene Jensen, 2022 laureate, and Rebekka Wild, 2023 laureate. To celebrate this success and highlight their research projects, a ceremony was held at the IBS on December 13, 2023, in the presence of Armand de Boissière, General Secretary of (…)

A model for the genome organisation of the virus responsible for influenza is proposed on the basis of a tool developed from recombinant viral nucleoprotein and synthetic RNA. In an article published in the journal Science Advances, scientists used cryo-electron microscopy to study the assembly of the influenza nucleoprotein into a helix, thereby providing details of the protein-protein and protein-RNA interactions within the nucleocapsid. Since October 2021, Europe is suffering the most (…)

Olfaction is critical for insects but it is also of interest in human and animal health as target for repellents strategy, especially against biting insects or for pheromone traps against pests. In winged insects, olfactory receptors (OR) form complexes composed of odorant-binding subunits (ORx) and with odorant receptor co-receptor subunits (Orco). These subunits have evolved in opposite directions, with a large divergence of the OR subunits for recognizing various ligands, while the Orco (…)

Photolyase is an enzyme harnessing visible light to repair a DNA strand that has been damaged by UV light. In a study published in Science, researchers have used X-rays from free electron lasers to reveal the atomic details of the molecular repair mechanism of a damaged DNA strand. To do this, they have used time-resolved crystallography on a time scale from hundreds of picoseconds to hundreds of microseconds. Antoine Royant and Sylvain Engilberge, from the Synchrotron group of the IBS, (…)

Rebekka Wild, team leader in the "Structure and activity of glycosaminoglycans" group at IBS, has been awarded the Impulscience® grant by the Bettencourt Schueller Foundation for her work wich aims to better understand the biosynthesis of these long sugar chains. Understanding better the biosynthesis of these chains will help to develop drugs that modify the structure of these long sugar chains and thus protect cells against viral infections or cancer ( details).

Seedling roots, post-germination, need to grow quickly to anchor the growing plant in the soil. However, the growth is regulated by ascertaining that the environment is satisfactory for the plant. When encountering a stress in the soil, roots have a very limited number of options: it can stop growing, it can develop secondary roots, it can change direction. Often, all these options are combined. Plant roots grow by cell division and cell elongation. One or both processes can be altered (…)

Compared to X-ray crystallography, electron crystallography can be performed on nanometer-sized crystals and can provide additional information, such as ion valency, from the resulting Coulomb potential map (Acta Cryst. D 2021, 77, 75- 85). Although electron crystallography has successfully resolved three-dimensional protein structures from vitrified crystals, its widespread use as a structural biology tool is limited. One of the reasons for this is the fragility of these crystals, which can (…)

The European Research Council (ERC) has just awarded an Advanced Grant to Jérôme Boisbouvier, a researcher at the Grenoble Institute de Biologie Structurale (IBS/Biomolecular NMR Spectroscopy Group), to develop new routes to study extra-large biomolecular assemblies using solution-state NMR. To know more

Bacterial wall maintenance, and in particular the peptidoglycan that forms the basis of bacterial cell wall scaffolding, is one of the main targets of antibiotics, and understanding its fine regulation is crucial to effectively combating resistance phenomena. Researchers from the NMR group at IBS, in collaboration with a group of Polish microbiologists, studied the high lytic activity of the enzymes Lysostaphin and LytM against the bacterium S. aureus, by targeting the glycil-glycine (…)

Lactate dehydrogenase (LDH) is a key metabolic enzyme. In eukaryotes, and in humans in particular, it contributes to the maintenance of an essential metabolic pathway, glycolysis, in the event of anaerobic stress. It is also involved in cell-to-cell communication mechanisms. These include interactions between healthy and cancerous cells and communication between neurons. In fact, it is one of the most studied enzymes. Structurally, human LDHs can be distinguished from their bacterial (…)

During meiosis, the formation of DNA double-strand breaks by the catalytic complex SPO11/TOPOVIBL and their repair through meiotic recombination are crucial mechanisms for the precise segregation of homologous chromosomes and the formation of gametes. However, the formation of these breaks can be dangerous and lead to undesirable chromosomal rearrangements if they are not introduced at the appropriate time and repaired correctly. Therefore, the activity of the SPO11-TOPOVIBL complex is (…)

Avian influenza viruses represents a recurring threat to human health. In particular highly pathogenic zoonotic avian strains, such as the currently circulating H5N1, can adapt to infect humans with high mortality, posing a catastrophic pandemic threat. Host adaptation is necessary for efficient replication and sustained human-to-human transmission. Amongst other adaptations, efficient replication in human cells requires mutations on the surface of the viral polymerase - the machine (…)

Researchers at the Institute of Structural Biology (IBS), in collaboration with the Laboratory of Metal Chemistry and Biology (LCBM), are investigating how the immune system responds when it encounters a threat. They are studying how certain substances, known as "alarmins," communicate with the complement defense system to alert and assist in repairing damage once the threat is under control. In their work, they are focusing on HMGB1, a protein normally located in the cell nucleus. However, (…)

LipoPolySaccharides are a hallmark of Gram-negative bacteria and their presence at the cell surface is key for bacterial integrity. As surface exposed components, they are recognized by immunity C-type lectin receptors present on Antigen Presenting Cells. Human Macrophage Galactose Lectin binds E. coli surface that presents a specific glycan motif. Nevertheless, this high affinity interaction occurs regardless of the integrity of its canonical calcium-dependent glycan binding site. Nuclear (…)

The order Bunyavirales includes a large number of viruses that have a segmented negative-stranded RNA genome (sNSV). Divided into 12 families, some Bunyaviruses are major human pathogens, such as Lassa virus and Crimean Congo virus. Other viruses are emerging, such as Hantaviruses, which mainly infect arthropods and rodents, but can also infect humans, causing encephalitis or haemorrhagic fevers. There are currently no drugs or vaccines available to counter these viruses. In this context, (…)

Structural biology methods have often benefited from their cryogenic version. X-ray crystallography and electron microscopy have been revolutionized by the possibility to flash cool biological samples, reducing radiation damage or better preserving the native state of the investigated macromolecules, respectively. With the development of super-resolution microscopy (nanoscopy), the question now arises of moving towards cryo-nanoscopy. The approach has already been demonstrated by several (…)

Modifications in the exposure of molecules at surface of abnormal cells, or those dying by apoptosis, ordinarily lead to their elimination by macrophages (phagocytosis). These changes are impaired in the tumor context and this can impede phagocytosis and cause resistances to therapies. Using super-resolution fluorescence microscopy, also known as nanoscopy, because it can achieve a resolution of a few nanometers, researchers of the IBS/I2SR group have studied the distribution, diffusion and (…)

De novo lipogenesis (DNL) is the metabolic pathway primarily utilized by the liver and adipose tissue to synthesize fatty acids from excess carbohydrates. An increased rate of DNL is observed in many characteristically "Western" diseases of affluence, such as type 2 diabetes and cardiovascular disease. Metabolic changes can lead to an altered expression of DNL genes through the acetylation of histones, the proteins that package DNA, but the molecular details remain poorly understood. A (…)