Studies of protein toxins – membrane interaction

Team of work

Herlax, Vanesa
Principal Investigator
Maté, Sabina María
Vázquez, Romina Florencia
Research Fellow
Cane, Lucia
Research Fellow
Pucci Molineris, Melisa
Research Fellow
Bernasconi, Ana
Support staff
Strack, Karen
Thesis Students
Hernández, Laura Edith
Support staff

Collaborators from other institutions


Guzmán, Fanny
Núcleo de Biotecnología Curauma (NBC), Pontificia Universidad Católica de Valparaíso (PUCV), Chile.

Muñoz Garay, Carlos
Instituto de Biotecnología de la Universidad Nacional Autónoma de México (UNAM), México.

Ostuni, Mariano
Institut National de la Transfusion Sanguine, Université Paris Diderot, Paris, France


Bakas, Laura

Centro de Investigación de Proteínas Vegetales (CIPROVE), Facultad de Ciencias Exactas, UNLP. La Plata. prov. de Buenos Aires. Argentina

Schwarzbaum, Pablo
Instituto de Química y Fisicoquímica Biológica, Facultad de Farmacia y Bioquímica, UBA. Buenos Aires, Argentina

Line overview

In Argentina Escherichia coli causes 75% to 90% of urinary infection episodes, prevailing in neonatal and pediatric urinary infections, in uncomplicated or recurrent cystitis of fertile women as well as in pyelonephritis. These strains are called uropathogenic E. coli (UPEC). Their capacity to invade and colonize other tissues is determined by a set of factors that includes: adherence factors, toxins, iron acquisition systems (siderophores) and capsular antigens. Within toxins these strains secrete, alpha hemolysin and cytotoxic necrotizing factor (CNF-1) are found. Both have shown high correlation with septicemia and kidney failure. In our laboratory we are engaged in the study of the mechanism of action of the alpha-hemolysin (HlyA) toxin in erythrocytes, in not only lytic but also sublytic concentrations. The study of the structure-function relationship of the protein using model system is also within our scope of work.



  • Relationship between intracellular calcium and morphologic changes in rabbit erythrocytes: Effects of the acylated and unacylated forms of E. coli alpha-hemolysin.
    Vazquez, R; Mate, S; Bakas, L; Garcia Muñoz, C; Herlax, V.
    2016. Biochimica et biophysica acta-biomembranes, Amsterdam: ELSEVIER SCIENCE BV, vol. 1858, n° 8, p. 1944-1953. ISSN 0005-2736
  • The unfavorable lipid environment reduced caveolin-1 expression in apical membranes from humanpreeclamptic placentas.
    Levi, L; Castro Parodi, M; Martínez, N; Piehl, L; Rubín De Celis, E; Herlax, V; Mate, S; Farina, M; Damiano, A. E.
    2016. Biochimica et Biophysica Acta-Biomembranes. Amsterdam: ELSEVIER SCIENCE BV, vol. 1858, n° 9, p. 2171-2180. ISSN 0005-2736
  • Induction of eryptosis by low concentrations of E. coli alpha-hemolysin.
    Carrizo, F; Maté, S; Bakás, L; Herlax, V.
    Biochimica et Biophysica Acta-Biomembranes. , Amsterdam: ELSEVIER SCIENCE BV, vol. 1848, p. 2779
    -2788. ISSN 0005-2736

  • Boundary region between coexisting lipid phases as initial binding sites for Escherichia coli alpha-hemolysin: a real-time study.
    Maté, S; Vázquez, R; Herlax, V; Daza-Millone, M, A; Fanani, M. L; Maggio, B; Vela, M. E; Bakás, L. 
    2014. Biochimica et Biophysica acta-Biomembranes. : ELSEVIER SCIENCE BV,. vol. 1838, p. 1832-1841. ISSN 0005-2736

  • N-nervonoylsphingomyelin (c24:1) prevents lateral heterogeneity in cholesterol-containing membranes.
    Maté, S; Busto, J; García-Arribas, A; Sot, J; Vázquez, R; Herlax, V; Wolf, C; Bakás, L; Goñi, F. M. 
    2014. Biophysical Journal. , United States: CELL PRESS,. vol. 106, p. 2606-2616. ISSN 0006-3495

  • Novel evidence for the specific interaction between cholesterol and alpha- haemolysin of Escherichia coli.
    Vázquez, R. F; Maté, S. M; Bakás, L, S; Fernández, M. M; Malchiodi, E. L; Herlax, V. S. 
    2014. Biochemical Journal. , Londres: PORTLAND PRESS LTD,. vol. 458, n° 3, p. 481-489. ISSN 0264-6021

  • Mecanismo de acción de la toxina alfa hemolisina de Escherichia coli. 
    Bakás, L; Maté, S; Vazquez, R; Herlax, V. 
    2013. Acta bioquímica clínica latinoamericana. La Plata: Federacion Bioquimica
    Provincia Buenos Aires. vol. 47, n° 2, p. 353-361. ISSN 0325-2957

  • Mecanismo de acción de la toxina alfa hemolisina de Escherichia coli. 
    Bakás, L; Maté, S; Vazquez, R; Herlax, V. 
    2013. Acta bioquímica clínica latinoamericana. La Plata: Federacion Bioquimica
    Provincia Buenos Aires. vol. 47, n° 2, p. 353-361. ISSN 0325-2957

  • E.coli Alpha Hemolysin and properties 
    Bakás, L; Maté, S; Vazquez, R; Herlax, V.
    2012. Biochemistry, BooK I, Ed. Prof. Deniz Ekinci, Croacia.
  • Contribution of the C-terminal end of apolipoprotein AI to neutralization of lipopolysaccharide endotoxic effect. 
    Henning, M, F; Herlax, V;Bakas, L. 
    2011. Innate Immunity 17 (3): 327 - 337
  • Alpha hemolysin induces and increases of erythrocytes Calcium: A FLIM 2.Photon Phasor Analysis Approach.
    Sánchez, S; Bakas, L; Graton, E; Herlax V.
    2011. PLos One 2011, 6 (6) e21127. Editorial: PLos One.
  • Eriptrosis, la muerte suicida de eritrocitos: mecanismo y enfermedades asociadas.
    Herlax, V; Vázquez, R; Mate, S; Bakas, L. 
    2011. Acta Bioquimica Clinica Latinoamericana Actualización45 (2): 287-96. Editorial: Publicación de Federación Bioquímica de la Provincia de Buenos Aires
  • The lytic mechanism of Escherichia coli á-hemolysin associated to outer membrane vesicles.
    Herlax, V; Henning, M. F; Bernasconi, A. M; Goñi, F. M; Bakás, L. 
    2010. Health. Scientific Research Publishing. vol. 2, n°5, p. 484-492. ISSN 1949-4998
  • Visualization and analysis of lipopolysaccharide distribution in binary phospholipid bilayers. 
    Henning, M. F; Sanchez, S; Bakas, L. 
    2009. Biochemical and biophysical research communications. Elsevier, vol.383, p. 22-26

  • Relevance of fatty acid covalently bound to Escherichia coli alpha-Hemolysin and membrane microdomains in the oligomerization process.
    Herlax, V; Maté, S; Rimoldi, O; Bakas, L. 
    2009. Journal of Biological Chemistry. Amer Soc Biochemistry Molecular Biology, Inc, vol. 284, p. 25199-25210
  • Fatty acids covalently bound to a-hemolysin of Escherichia coli are involved in the molten globule conformation: Implication of disorder regions in the binding promiscuity. 
    Herlax, V; Bakas, L. 
    2007. Biochemistry. vol. 46, p. 5177-5184
     ISSN 0006-2960

  • Paradoxical lipid dependence of pores formed by Escherichia coli α-hemolysin in planar phospholipids bilayer membranes
    Bakás, L; Chanturiya, A; Herlax, V; Zimmerberg, J. 
    2006. Biophysical J.  91:3748-3755. ISSN: 0006-349591

  • Role of lipopolisacharide on the structure and function of HlyA from Escherichia coli
    Herlax, V; de Alaniz, M. J.T; Bakás, L.
    2005. Chem Phys Lipids. 135(2):107-115. ISSN: 0009-3084

  • Acyl chains are responsable for irreversibility in the Escherichia coliα-Hemolysin binding to membrane
    Herlax, V; Bakás, L.
    2003. Short Communication, Chem.Phys.Lipids 122 185-190.  ISSN: 0009-3084

  • Aplicaciones terapéuticas de toxinas líticas formadoras de poros: potencialidades de a- hemolisina de Escherichia coli
    Herlax, V; Bakás, L.
    2001. Medicina, 62:66-72 (artículo especial). ISSN 0025-7680

Book - Book chapters

  • Alfa- Hemolisina de Escherichia coli: Prototipo de las toxinas RTX (Repeat in Toxin). Un estudio de las etapas de su mecanismo de acción.
    Vázquez, R; Maté, S; Herlax, V; Bakás, L; Álvarez Valcárcel, C; Pazos Santos, F.
    2016. Puebla: Benemérita Universidad Autónoma De Puebla, p. 191-213. ISBN 978-607-525-046-5

  • Role of sphingomyelin in membrane-domain formation and the influence on protein interaction: focusing on the nanometer scale.
    Maté, S; Herlax, V; Vázquez, R; Bakás, L.
    2016. Nueva York: NovaScience Publishers, p. 89-112. ISBN 978-1-63484-581-6

  • E. coli Alpha Hemolysin and Properties. 
    Bakás, L; Maté, S; Vázquez, R; Herlax, V.
    2012. InTech, p. 107-140. ISBN 978-953-51-0076-8

  • Interacción lípido-proteína: Mecanismo de acción de alfa hemolisina de E. Coli.
    Vanesa Herlax. 
    2012. Editorial Académica Española, 2012. p. 160

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