Université de Fribourg

Kinetics and mechanism of mineral respiration: how iron hemes synchronize electron transfer rates

Chabert, Valentin ; Babel, Lucille ; Füeg, Michael P. ; Karamash, Maksym ; Madivoli, Edwin S. ; Herault, Nelly ; Dantas, Joana M. ; Salgueiro, Carlos A. ; Giese, Bernd ; Fromm, Katharina M.

In: Angewandte Chemie International Edition, 2020, vol. 59, no. 30, p. 12331-12336

Anaerobic microorganisms of the Geobacter genus are effective electron sources for the synthesis of nanoparticles, for bioremediation of polluted water, and for the production of electricity in fuel cells. In multistep reactions, electrons are transferred via iron/heme cofactors of c‐type cytochromes from the inner cell membrane to extracellular metal ions, which are bound to outer membrane...

Université de Fribourg

Sequential multiple-target sensor: In3+, Fe2+, and Fe3+ discrimination by an anthracene-based probe

Finelli, Alba ; Chabert, Valentin ; Hérault, Nelly ; Crochet, Aurélien ; Kim, Cheal ; Fromm, Katharina M.

In: Inorganic Chemistry, 2019, vol. 58, no. 20, p. 13796–13806

Indium is a nonphysiological toxic metal widely used in industry. While misunderstood, its toxicity is proposed to be linked to a perturbation of Fe3+ homeostasis through the binding of In3+ ions to essential iron metalloproteins such as transferrins. Therefore, the monitoring of In3+ and Fe3+ in biological environments is of prime interest for both basic research and diagnosis. Here we...

Université de Fribourg

Alpha-helical folding of SilE models upon Ag(His)(Met) motif formation

Chabert, Valentin ; Hologne, Maggy ; Sénèque, Olivier ; Walker, Olivier ; Fromm, Katharina M.

In: Chemical Communications, 2018, vol. 54, no. 74, p. 10419–10422

The SilE protein is suspected to have a prominent role in Ag+ detoxification of silver resistant bacteria. Using model peptides, we elucidated both qualitative and quantitative aspects of the Ag+-induced α-helical structuring role of His- and Met-rich sequences of SilE, improving our understanding of its function within the Sil system.

Université de Fribourg

WRINKLED1 and ACYL‐COA:DIACYLGLYCEROL ACYLTRANSFERASE1 regulate tocochromanol metabolism in Arabidopsis

Pellaud, Sébastien ; Bory, Alexandre ; Chabert, Valentin ; Romanens, Joëlle ; Chaisse-Leal, Laurie ; Doan, Anh Vu ; Frey, Lucas ; Gust, Andrea ; Fromm, Katharina M. ; M?ne-Saffrané, Laurent

In: New Phytologist, 2018, vol. 217, no. 1, p. 245–260

Photosynthetic organisms such as plants, algae and some cyanobacteria synthesize tocochromanols, a group of compounds that encompasses tocopherols and tocotrienols and that exhibits vitamin E activity in animals. While most vitamin E biosynthetic genes have been identified in plant genomes, regulatory genes controlling tocopherol accumulation are currently unknown.We isolated by forward ...

Université de Fribourg

Model peptide studies of Ag+ binding sites from the silver resistance protein SilE

Chabert, Valentin ; Hologne, M. ; Sénèque, O. ; Crochet, Aurélien ; Walker, O. ; Fromm, Katharina M.

In: Chemical Communications, 2017, vol. 53, no. 45, p. 6105–6108

Using model peptides, each of the nine MX2H or HXnM (n = 1, 2) motifs of the silver resistance protein SilE has been shown to coordinate to one Ag+ ion by its histidine and methionine residues with Kd in the μM range. This suggests an Ag+ buffering role for SilE in the case of high Ag+ overload.

Université de Fribourg

Towards cardiolite-inspired carbon monoxide releasing molecules – Reactivity of d4, d5 rhenium and d6 manganese carb­onyl complexes with isocyanide ligands

Kottelat, Emmanuel ; Chabert, Valentin ; Crochet, Aurélien ; Fromm, Katharina M. ; Zobi, Fabio

In: European Journal of Inorganic Chemistry, 2015, vol. 2015, no. 34, p. 5628–5638

Carbon monoxide releasing molecules (CORMs) are investigated widely in synthetic and medicinal chemistry owing to the potential therapeutic applications of the CO gas. Organometallic carbonyl complexes are best suited to play the role of CO carriers as they allow the exogenous release of CO under controlled conditions, and the toxicity of the gas can be overcome. With the long-term goal of...