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

α-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, an...

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Autores principales: Maté, Sabina María, Vázquez, Romina Florencia, Herlax, Vanesa Silvana, Daza Millone, María Antonieta, Fanani, María L., Maggio, Bruno, Vela, María Elena, Bakás, Laura Susana
Formato: Articulo
Lenguaje:Inglés
Publicado: 2014
Materias:
Ciencias Exactas
Liquid-disordered phase
Liquid-ordered phase
Monolayer
Pore-forming toxin
Supported lipid bilayer
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/85271
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-85271
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Liquid-disordered phase
Liquid-ordered phase
Monolayer
Pore-forming toxin
Supported lipid bilayer
spellingShingle Ciencias Exactas
Liquid-disordered phase
Liquid-ordered phase
Monolayer
Pore-forming toxin
Supported lipid bilayer
Maté, Sabina María
Vázquez, Romina Florencia
Herlax, Vanesa Silvana
Daza Millone, María Antonieta
Fanani, María L.
Maggio, Bruno
Vela, María Elena
Bakás, Laura Susana
Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
topic_facet Ciencias Exactas
Liquid-disordered phase
Liquid-ordered phase
Monolayer
Pore-forming toxin
Supported lipid bilayer
description α-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.
format Articulo
Articulo
author Maté, Sabina María
Vázquez, Romina Florencia
Herlax, Vanesa Silvana
Daza Millone, María Antonieta
Fanani, María L.
Maggio, Bruno
Vela, María Elena
Bakás, Laura Susana
author_facet Maté, Sabina María
Vázquez, Romina Florencia
Herlax, Vanesa Silvana
Daza Millone, María Antonieta
Fanani, María L.
Maggio, Bruno
Vela, María Elena
Bakás, Laura Susana
author_sort Maté, Sabina María
title Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
title_short Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
title_full Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
title_fullStr Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
title_full_unstemmed Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: A real-time study
title_sort boundary region between coexisting lipid phases as initial binding sites for escherichia coli alpha-hemolysin: a real-time study
publishDate 2014
url http://sedici.unlp.edu.ar/handle/10915/85271
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