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|Title:||Membrane-pore forming characteristics of the bordetella pertussis cyaa-hemolysin domain|
Biophysics Institute for Research and Development (BIRD)
|Citation:||Toxins. Vol.7, No.5 (2015), 1486-1496|
|Abstract:||© 2015 by the authors; licensee MDPI, Basel, Switzerland. Previously, the 126-kDa Bordetella pertussis CyaA pore-forming/hemolysin (CyaA-Hly) domain was shown to retain its hemolytic activity causing lysis of susceptible erythrocytes. Here, we have succeeded in producing, at large quantity and high purity, the His-tagged CyaA-Hly domain over-expressed in Escherichia coli as a soluble hemolytically-active form. Quantitative assays of hemolysis against sheep erythrocytes revealed that the purified CyaA-Hly domain could function cooperatively by forming an oligomeric pore in the target cell membrane with a Hill coefficient of ~3. When the CyaA-Hly toxin was incorporated into planar lipid bilayers (PLBs) under symmetrical conditions at 1.0 M KCl, 10 mM HEPES buffer (pH 7.4), it produced a clearly resolved single channel with a maximum conductance of ~35 pS. PLB results also revealed that the CyaA-Hly induced channel was unidirectional and opened more frequently at higher negative membrane potentials. Altogether, our results first provide more insights into pore-forming characteristics of the CyaA-Hly domain as being the major pore-forming determinant of which the ability to induce such ion channels in receptor-free membranes could account for its cooperative hemolytic action on the target erythrocytes.|
|Appears in Collections:||Scopus 2011-2015|
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