Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process

α-Hemolysin (HlyA) is an exotoxin secreted by some pathogenic strains of Escherichia coli that causes lysis of several mammalian cells, including erythrocytes of different species. HlyA is synthesized as a protoxin, pro-HlyA, which is activated by acylation at two internal lysines Lys-563 and Lys-68...

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Autores principales: Herlax, Vanesa Silvana, Maté, Sabina María, Rimoldi, Omar Jorge, Bakás, Laura Susana
Formato: Articulo
Lenguaje:Inglés
Publicado: 2009
Materias:
Ciencias Médicas
Bioquímica
Proteínas Hemolisinas
Escherichia coli
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/82724
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-82724
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Médicas
Bioquímica
Proteínas Hemolisinas
Escherichia coli
spellingShingle Ciencias Médicas
Bioquímica
Proteínas Hemolisinas
Escherichia coli
Herlax, Vanesa Silvana
Maté, Sabina María
Rimoldi, Omar Jorge
Bakás, Laura Susana
Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
topic_facet Ciencias Médicas
Bioquímica
Proteínas Hemolisinas
Escherichia coli
description α-Hemolysin (HlyA) is an exotoxin secreted by some pathogenic strains of Escherichia coli that causes lysis of several mammalian cells, including erythrocytes of different species. HlyA is synthesized as a protoxin, pro-HlyA, which is activated by acylation at two internal lysines Lys-563 and Lys-689. It has been proposed that pore formation is the mechanism of cytolytic activity for this toxin, as shown in experiments with whole cells, planar lipid membranes, and liposomes, but these experiments have yielded conflicting results about the structure of the pore. In this study, HlyA cysteine replacement mutant proteins of amino acids have been labeled with Alexa-488 and Alexa-546. Fluorescence resonance energy transfer measurements, employing labeled toxin bound to sheep ghost erythrocytes, have demonstrated that HlyA oligomerizes on erythrocyte membranes. As the cytotoxic activity is absolutely dependent on acylation, we have studied the role of acylation in the oligomerization, demonstrating that fatty acids are essential in this process. On the other hand, fluorescence resonance energy transfer and the hemolytic activity decrease when the erythrocyte ghosts are cholesterol-depleted, hence indicating the role of membrane microdomains in the clustering of HlyA. Simultaneously, HlyA was found in detergent-resistant membranes. Pro-HlyA has also been found in detergent-resistant membranes, thus demonstrating that the importance of acyl chains in toxin oligomerization is the promotion of protein-protein interaction. These results change the concept of the main role assigned to acyl chain in the targeting of proteins to membrane microdomains.
format Articulo
Articulo
author Herlax, Vanesa Silvana
Maté, Sabina María
Rimoldi, Omar Jorge
Bakás, Laura Susana
author_facet Herlax, Vanesa Silvana
Maté, Sabina María
Rimoldi, Omar Jorge
Bakás, Laura Susana
author_sort Herlax, Vanesa Silvana
title Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
title_short Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
title_full Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
title_fullStr Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
title_full_unstemmed Relevance of fatty acid covalently bound to Escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
title_sort relevance of fatty acid covalently bound to escherichia coli α-hemolysin and membrane microdomains in the oligomerization process
publishDate 2009
url http://sedici.unlp.edu.ar/handle/10915/82724
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AT rimoldiomarjorge relevanceoffattyacidcovalentlyboundtoescherichiacoliahemolysinandmembranemicrodomainsintheoligomerizationprocess
AT bakaslaurasusana relevanceoffattyacidcovalentlyboundtoescherichiacoliahemolysinandmembranemicrodomainsintheoligomerizationprocess
bdutipo_str Repositorios
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