2020

How to determine if an insecticide is environmentally safe? This is the question addressed by the Canadian TV (RadioCanada) as part of the show “The Green Week” in a documentary in which Guillaume Tetreau has been interviewed for its expertise on this topic. This documentary (in French), entitled « Le Bti, un larvicide inoffensif ? » and broadcasted saturday 18th April 2020, is available in replay on RadioCanada website (…)

Radical S-adenosyl-L-methionine (SAM) enzymes belong to a vast family of catalysts. They use the one electron reduction of a [Fe4S4] cluster to cleave SAM, producing a highly reactive 5´-deoxyadenosyl radical species. The latter in turn triggers a wide variety of radical-based reactions on substrates as different as small organic molecules, proteins, DNA or RNA. The challenging reactions they catalyse makes them very promising catalysts for diverse biotechnological applications. However, the (…)

Joanna Timmins, researcher in the Viral Infection and Cancer group at the IBS, sheds light on the role of Structural Biology in the fight against Covid-19. Her contribution, accessible to anyone curious about science, is available on the website of the European Crystallographic Association. Please find it here.

Many viruses are known to form cellular compartments, also called viral factories. Paramyxoviruses, including measles virus, colocalize their proteomic and genomic material in puncta in infected cells. Researchers from FDP, VRM and IRPAS groups at IBS demonstrate that purified nucleo- (N) and phospho- (P) proteins of Measles virus form liquid-like membraneless organelles upon mixing in vitro. They identify weak interactions involving intrinsically disordered domains of N and P that are (…)

The bacterial protein RsrR that coordinates a [2Fe-2S] cluster, regulates the expression of genes involved either directly or indirectly in cell redox equilibrium. The redox state of this iron-sulfur cluster controls RsrR binding to its site in DNA; only the +2 oxidized form binds to the nucleic acid. In 2019, the IBS/Metallo group in collaboration with Pr. Nick Le Brun (University of East Anglia, UK) published the crystal structure of RsrR (Volbeda et al., JACS 2019) that showed an (…)

How can mosquito populations be reduced without impacting the environment or inducing resistance? This double challenge is met by mosquitocidal bacterium Bacillus thuringiensis israelensis (Bti), which produces, in the form of nanocrystals, four toxins that specifically target mosquito larvae, thereby preventing the transmission of serious diseases such as malaria, dengue fever or chikungunya. Among the four toxins produced by Bti, researchers from a consortium of 11 laboratories led by the (…)

X-ray crystallography is the most prolific method to determine the structure of biological macromolecules – i.e. proteins, DNA, RNA and complexes thereof. It is limited by the strong damage inflicted to biological molecules by exposure to X-rays. To mitigate damage progression, crystallographic data collection has for the past decades been carried out mostly at cryogenic temperatures, yet at the risk of blocking conformational heterogeneity that can be central to biological function. The (…)

Photoswitchable fluorescent proteins are used as molecular markers in super-resolution light microscopy that images life biological cells at a resolution of a few tens of nanometers. These proteins can be reversibly toggled between a non-fluorescent (off) state and a fluorescent (on) state by irradiation with light at specific wavelengths. Photoswitching between on and off states involves ultra-fast excited-state processes that have been recently characterized structurally. Conformational (…)