[FeFe]-hydrogenase active site assembly machinery

To tackle the climate crisis, humanity urgently needs renewable and decarbonized energy sources. A promising solution lies in harnessing dihydrogen (H2), and enzymes known as [FeFe] hydrogenases can play a vital role in its production. These enzymes catalyze the reversible oxidation of dihydrogen, employing an active site called the "H-cluster," a complex organometallic structure. The intricate biosynthesis of this cluster involves three maturation proteins: HydG, HydE, and HydF. Despite recent progress, a full understanding of this process remains elusive due to the complexity of the chemical reactions involved. Our goal is to conduct a structural study combined with step-by-step reaction monitoring using spectroscopy. This approach aims to identify and characterize various reaction intermediates of one key enzyme in the process. This collaborative project involves two leading CEA teams specializing in the study of oxygen-sensitive metalloproteins. The doctoral student will benefit from an ideal scientific and technical environment to achieve this objective, crucially important for advancing hydrogen economy development.

Molecular probes to capture lanthanide-protein interactions

Recent technological developments have expanded and intensified the use of lanthanides in domains as diverse as renewable energy, computing, and medicine. Increasing usage of these metals raises the question of their extraction and recycling. Some bacteria and plants extract and accumulate selectively these metals. Understanding the molecular mechanisms underlying this feature is a milestone towards innovative bioremediation and bioinspired extraction strategies. Nevertheless, identifying protein-metal interactions remains challenging due to the transient character of these interactions. Here, we propose an innovative chemical biology approach for the labelling of proteins interacting with lanthanides. The PhD student will synthesize molecular probes composed of a detection module for the metal, a tag module to label the interacting protein, and an activatable linker that will enable the labelling of the protein only if interacting with a metal. They will use these chemical tools to investigate the metal interactome in bacteria or plant cells. We will thus decipher what are the key biological interactors of lanthanides, their roles in living systems and the features that enable efficient binding to metals. We expect that our findings will give insights into the toxicology of those elements and inform environmental and occupational safety policies. On the longer term, new bio-inspired strategies for their extraction, recycling, decorporation and remediation will arise from the molecular understanding of metal-life interactions, enabling a well thought-out usage of these elements to support the environmental and numerical transitions.