Société Française de Biochimie et Biologie Moléculaire


JULY 2022 - Florent Canonico

SAYENS, Vandoeuvre-les-NancyProbing the mechanism of peroxiredoxin decamer interaction with its reductase sulfiredoxin from the single molecule to the solution scale
Nanoscale Horizons (2022) 7(5):515-525.doi:10.1039/d2nh00037g
Beaussart A, Canonico F, Mazon H, Hidalgo J, Cianférani S, Le Cordier H, Kriznik A, Rahuel-Clermont S.

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Florent Canonico, 30 years old, prepared his thesis under the supervision of Dr. Sophie Rahuel-Clermont, Dr. Hortense Mazon and Dr. Audrey Beaussart at the University of Lorraine in the Molecular and Structural Enzymology team of the IMOPA laboratory. He is currently a project manager in charge of innovation in biotechnology in the Grand Est region. He completed his studies at the University of Lorraine and specialized in molecular enzymology at the IMoPA laboratory, on the molecular mechanisms of sulfurtransferases and then on the interaction mechanisms of peroxyredoxins with their redox partners. In the antioxidant arsenal of a cell, Peroxyredoxins detoxify peroxides and play a crucial role due to their abundance and their implication in diseases such as cancers or inflammatory diseases. The action of Peroxyredoxins is intimately linked to their ring-like architecture composed of 10 units. By a multiscale experimental strategy combining atomic force microscopy, mass spectrometry, fast kinetics, the dynamics of the multivalent interaction of Sulfiridoxin with each of the subunits constituting Peroxyredoxin was observed, showing the impact of these interactions on the ring structure and the importance of protein flexibility in this interaction, on which the biological regulation of these enzymes depends. This work represents an important step in the understanding of the role of the decameric structure of Peroxyredoxin in its cellular functions and opens the way to the study of the interactions of various oligomeric proteins.

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Résumé de l'article

Peroxiredoxins from the Prx1 subfamily (Prx) are highly regulated multifunctional proteins involved in oxidative stress response, redox signaling and cell protection. Prx is a homodimer that associates into a decamer. The monomer C-terminus plays intricate roles in Prx catalytic functions, decamer stability and interaction with its redox partner the small reductase Sulfiredoxin (Srx), that regulates the switch between Prx cellular functions. As only static structures of covalent Prx-Srx complexes have been reported, whether Srx binding dissociates the decameric assembly and how Prx subunit flexibility impacts complex formation is unknown. Here, we assessed the non-covalent interactions mechanism and dynamics in solution of Saccharomyces cerevisiae Srx with the Prx Tsa1 ten subunits at the decamer level via a combination of multiscale biophysical approaches including native mass spectrometry. We show that the ten subunits of the decamer can be saturated by ten Srx molecules and that the Tsa1 decamer in complex with Srx does not dissociate in solution. Furthermore, the binding events of atomic force microscopy (AFM) tip-grafted Srx molecules to Tsa1 individual subunits were relevant to interactions between free molecules in solution. Combined with protein engineering and rapid kinetics, the observation of peculiar AFM force-distance signatures revealed that Tsa1 C-terminus flexibility controls Tsa1/Srx two-step binding and dynamics and determines force-induced dissociation of Srx from each subunit of the decameric complex in a sequential or concerted mode. This combined approach from the solution to the single-molecule levels offers promising prospects for understanding oligomeric protein interaction with their partners.