%0 Journal Article %T ESAT-6 from Mycobacterium tuberculosis Dissociates from Its Putative Chaperone CFP-10 under Acidic Conditions and Exhibits Membrane-Lysing Activity %+ Génétique Moléculaire Bactérienne %+ Cryomicroscopie Moléculaire (Plate-forme) %+ Utrecht University [Utrecht] %+ Dynamique Structurale des Macromolécules (DSM) %+ Immunothérapie %+ Biophysique des Macromolécules et de leurs Interactions %A de Jonge, Marien, I %A Pehau-Arnaudet, Gérard %A Fretz, Marjan, M %A Romain, Felix %A Bottai, Daria %A Brodin, Priscille %A Honoré, Nadine %A Marchal, Gilles %A Jiskoot, Wim %A England, Patrick %A Cole, Stewart, T %A Brosch, Roland %Z This work received support from the Institut Pasteur (GPH-5), the European Commision, contract LHSP-CT-2005-018923 (NM4TB), the ACI Microbiologie (MIC0311), and the Association Française Raoul Follereau. Vectors pMRLB7 and pMRLB46 were received as part of NIH NIAID contract no. HHSN266200400091C, entitled “Tuberculosis Vaccine Testing and Research Materials,” which was awarded to Colorado State University. %< avec comité de lecture %@ 0021-9193 %J Journal of Bacteriology %I American Society for Microbiology %V 189 %N 16 %P 6028 - 6034 %8 2007-06-08 %D 2007 %R 10.1128/jb.00469-07 %M 17557817 %Z Life Sciences [q-bio]Journal articles %X The 6-kDa early secreted antigenic target ESAT-6 and the 10-kDa culture filtrate protein CFP-10 of Mycobacterium tuberculosis are secreted by the ESX-1 system into the host cell and thereby contribute to pathogenicity. Although different studies performed at the organismal and cellular levels have helped to explain ESX-1-associated phenomena, not much is known about how ESAT-6 and CFP-10 contribute to pathogenesis at the molecular level. In this study we describe the interaction of both proteins with lipid bilayers, using biologically relevant liposomal preparations containing dimyristoylphosphatidylcholine (DMPC), dimyristoylphosphatidylglycerol, and cholesterol. Using floatation gradient centrifugation, we demonstrate that ESAT-6 showed strong association with liposomes, and in particular with preparations containing DMPC and cholesterol, whereas the interaction of CFP-10 with membranes appeared to be weaker and less specific. Most importantly, binding to the biomembranes no longer occurred when the proteins were present as a 1:1 ESAT-6 ⅐ CFP-10 complex. However, lowering of the pH resulted in dissociation of the protein complex and subsequent protein-liposome interaction. Finally, cryoelectron microscopy revealed that ESAT-6 destabilized and lysed liposomes, whereas CFP-10 did not. In conclusion, we propose that one of the main features of ESAT-6 in the infection process of M. tuberculosis is the interaction with biomembranes that occurs after dissociation from its putative chaperone CFP-10 under acidic conditions typically encountered in the phagosome. %G English %Z We thank F. Livolant and A. Leforestier for the use of the cryofixation device developed in the Laboratoire de Physique des Solides, CNRS, URA 8502, Université Paris-Sud, Orsay, France, and C. Snel and L. Marsollier for their assistance and helpful discussions. We acknowledge the kind gift of DMPG from Lipoïd GmbH, Ludwigshafen, Germany %L pasteur-03525656 %U https://pasteur.hal.science/pasteur-03525656 %~ PASTEUR %~ CNRS %~ OPENAIRE