Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study

dc.creatorMaté, Sabina María
dc.creatorVázquez, Romina Florencia
dc.creatorHerlax, Vanesa Silvana
dc.creatorDaza Millone, María Antonieta
dc.creatorFanani, María L.
dc.creatorMaggio, Bruno
dc.creatorVela, María Elena
dc.creatorBakás, Laura Susana
dc.date2014
dc.date2019-11-08T18:29:08Z
dc.identifierhttp://sedici.unlp.edu.ar/handle/10915/85271
dc.identifierissn:0005-2736
dc.descriptionα-Hemolysin (HlyA) is a protein toxin, a member of the pore-forming Repeat in Toxin (RTX) family, secreted by some pathogenic strands of <i>Escherichia coli</i>. The mechanism of action of this toxin seems to involve three stages that ultimately lead to cell lysis: binding, insertion, and oligomerization of the toxin within the membrane. Since the influence of phase segregation on HlyA binding and insertion in lipid membranes is not clearly understood, we explored at the meso- and nanoscale - both <i>in situ</i> and in <i>real-time</i> - the interaction of HlyA with lipid monolayers and bilayers. Our results demonstrate that HlyA could insert into monolayers of dioleoylphosphatidylcholine/sphingomyelin/cholesterol (DOPC/16:0SM/Cho) and DOPC/24:1SM/Cho. The time course for HlyA insertion was similar in both lipidic mixtures. HlyA insertion into DOPC/16:0SM/Cho monolayers, visualized by Brewster-angle microscopy (BAM), suggest an integration of the toxin into both the liquid-ordered and liquid-expanded phases. Atomic-force-microscopy imaging reported that phase boundaries favor the initial binding of the toxin, whereas after a longer time period the HlyA becomes localized into the liquid-disordered (<i>Ld</i>) phases of supported planar bilayers composed of DOPC/16:0SM/Cho. Our AFM images, however, showed that the HlyA interaction does not appear to match the general strategy described for other invasive proteins. We discuss these results in terms of the mechanism of action of HlyA.
dc.descriptionInstituto de Investigaciones Bioquímicas de La Plata
dc.descriptionInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
dc.descriptionFacultad de Ciencias Exactas
dc.formatapplication/pdf
dc.format1832-1841
dc.languageen
dc.rightshttp://creativecommons.org/licenses/by-nc-sa/4.0/
dc.rightsCreative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.subjectCiencias Exactas
dc.subjectLiquid-disordered phase
dc.subjectLiquid-ordered phase
dc.subjectMonolayer
dc.subjectPore-forming toxin
dc.subjectSupported lipid bilayer
dc.titleBoundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
dc.typeArticulo
dc.typeArticulo


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