The 6-kDa early secreted antigenic target ESAT-6 and the 1O-kDa culture filtrate protein CFP-1O of Mycobacterium tubercuThsis 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-1O 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-1O 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 · CFP-1O 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-1O 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-1O under acidic conditions typically encountered in the phagosome. Copyright © 2007, American Society for Microbiology. All Rights Reserved.

ESAT-6 from Mycobacterium tuberculosis dissociates from its putative chaperone CFP-10 under acidic conditions and exhibits membrane-lysing activity

BOTTAI, DARIA;
2007-01-01

Abstract

The 6-kDa early secreted antigenic target ESAT-6 and the 1O-kDa culture filtrate protein CFP-1O of Mycobacterium tubercuThsis 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-1O 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-1O 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 · CFP-1O 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-1O 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-1O under acidic conditions typically encountered in the phagosome. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
2007
De Jonge, Marien I.; Pehau Arnaudet, Gérard; Fretz, Marjan M.; Romain, Felix; Bottai, Daria; Brodin, Priscille; Honoré, Nadine; Marchal, Gilles; Jiskoot, Wim; England, Patrick; Cole, Stewart T.; Brosch, Roland
File in questo prodotto:
File Dimensione Formato  
J. Bacteriol.-2007-de Jonge-6028-34.pdf

accesso aperto

Tipologia: Versione finale editoriale
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 317.35 kB
Formato Adobe PDF
317.35 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/813503
Citazioni
  • ???jsp.display-item.citation.pmc??? 138
  • Scopus 233
  • ???jsp.display-item.citation.isi??? ND
social impact