par Pagliaccia, C;Wang, Xiao-Ming;Tardy, Florence 
;Telford, J L;Ruysschaert, Jean Marie ;Cabiaux, Véronique
Référence European journal of biochemistry / FEBS, 267, 1, page (104-109)
Publication Publié, 2000-01
;Telford, J L;Ruysschaert, Jean Marie ;Cabiaux, Véronique Référence European journal of biochemistry / FEBS, 267, 1, page (104-109)
Publication Publié, 2000-01
Article révisé par les pairs
| Résumé : | In its mature form, the VacA toxin of Helicobacter pylori is a 95-kDa protein which is released from the bacteria as a low-activity complex. This complex can be activated by low-pH treatment that parallels the activity of the toxin on target cells. VacA has been previously shown to insert itself into lipid membranes and to induce anion-selective channels in planar lipid bilayers. Binding of VacA to lipid vesicles and its ability to induce calcein release from these vesicles were systematically compared as a function of pH. These two phenomena show a different pH-dependence, suggesting that the association with the lipid membrane may be a two-step mechanism. The secondary and tertiary structure of VacA as a function of pH and the presence of lipid vesicles were investigated by Fourier-transform infrared spectroscopy. The secondary structure of VacA is identical whatever the pH and the presence of a lipid membrane, but the tertiary structure in the presence of a lipid membrane is dependent on pH, as evidenced by H/D exchange. |
