%0 Journal Article %T Stability, structural and functional properties of a monomeric, calcium-loaded adenylate cyclase toxin, CyaA, from Bordetella pertussis. %+ Département de Biologie structurale et Chimie - Department of Structural Biology and Chemistry %+ Institut de Biologie Intégrative de la Cellule (I2BC) %A Cannella, Sara E %A Ntsogo Enguéné, Véronique Yvette %A Davi, Marilyne %A Malosse, Christian %A Sotomayor Pérez, Ana Cristina %A Chamot-Rooke, Julia %A Vachette, Patrice %A Durand, Dominique %A Ladant, Daniel %A Chenal, Alexandre %Z S.E.C. was supported by a stipend from the Pasteur - Paris University (PPU) International PhD Program; A.C.S.P. was supported by a PTR grant (PTR374). Running costs were supported by Institut Pasteur, PasteurInnov (PIV15-197), PTR grant (PTR451), CNRS, Fondation Recherche Médicale (FRM DBS20140930771). Funding for the LTQ-Orbitrap Velos acquisition was secured through a DIM Malinf grant from the region Ile-de-France. %< avec comité de lecture %@ 2045-2322 %J Scientific Reports %I Nature Publishing Group %V 7 %P 42065 %8 2017-02-10 %D 2017 %R 10.1038/srep42065 %M 28186111 %K Biophysical chemistry %K Permeation and transport %K SAXS %Z Life Sciences [q-bio]/Biochemistry, Molecular BiologyJournal articles %X Bordetella pertussis, the causative agent of whooping cough, secretes an adenylate cyclase toxin, CyaA, which invades eukaryotic cells and alters their physiology by cAMP overproduction. Calcium is an essential cofactor of CyaA, as it is the case for most members of the Repeat-in-ToXins (RTX) family. We show that the calcium-bound, monomeric form of CyaA, hCyaAm, conserves its permeabilization and haemolytic activities, even in a fully calcium-free environment. In contrast, hCyaAm requires sub-millimolar calcium in solution for cell invasion, indicating that free calcium in solution is involved in the CyaA toxin translocation process. We further report the first in solution structural characterization of hCyaAm, as deduced from SAXS, mass spectrometry and hydrodynamic studies. We show that hCyaAm adopts a compact and stable state that can transiently conserve its conformation even in a fully calcium-free environment. Our results therefore suggest that in hCyaAm, the C-terminal RTX-domain is stabilized in a high-affinity calcium-binding state by the N-terminal domains while, conversely, calcium binding to the C-terminal RTX-domain strongly stabilizes the N-terminal regions. Hence, the different regions of hCyaAm appear tightly connected, leading to stabilization effects between domains. The hysteretic behaviour of CyaA in response to calcium is likely shared by other RTX cytolysins. %G English %2 https://pasteur.hal.science/pasteur-01508525/document %2 https://pasteur.hal.science/pasteur-01508525/file/Cannella%20S_2017.pdf %L pasteur-01508525 %U https://pasteur.hal.science/pasteur-01508525 %~ PASTEUR %~ CEA %~ CNRS %~ CEA-UPSAY %~ I2BC %~ UNIV-PARIS-SACLAY %~ CEA-UPSAY-SACLAY %~ JOLIOT %~ CEA-DRF %~ TEST-HALCNRS %~ GS-ENGINEERING %~ GS-BIOSPHERA %~ GS-HEALTH-DRUG-SCIENCES %~ INSTITUT-SCIENCES-LUMIERE %~ FRM