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Calorimetric scrutiny of lipid binding by sticholysin II toxin mutants



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Alegre Cebollada, Jorge y Cunietti, Michela y Herrero Galán, Elías y Gavilanes, José G. y Martínez del Pozo, Álvaro (2008) Calorimetric scrutiny of lipid binding by sticholysin II toxin mutants. Journal of Molecular Biology, 382 . pp. 920-930. ISSN 0022-2836

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URL Oficial: http://www.elsevier.com/wps/find/journaldescription.cws_home/622890/description#description


The mechanisms by which pore-forming toxins are able to insert into lipid
membranes are a subject of the highest interest in the field of lipid–protein
interaction. Eight mutants affecting different regions of sticholysin II, a
member of the pore-forming actinoporin family, have been produced, and
their hemolytic and lipid-binding properties were compared to those of the
wild-type protein. A thermodynamic approach to the mechanism of pore
formation is also presented. Isothermal titration calorimetry experiments
show that pore formation by sticholysin II is an enthalpy-driven process
that occurs with a high affinity constant (1.7×108 M−1). Results suggest that
conformational flexibility at the N-terminus of the protein does not provide
higher affinity for the membrane, although it is necessary for correct pore
formation. Membrane binding is achieved through two separate mechanisms,
that is, recognition of the lipid–water interface by a cluster of aromatic
residues and additional specific interactions that include a phosphocholinebinding
site. Thermodynamic parameters derived from titration experiments
are discussed in terms of a putative model for pore formation.

Tipo de documento:Artículo
Palabras clave:Actinoporin, Equinatoxin, Hemolytic toxin, ITC, Lipid binding
Materias:Ciencias > Química > Química física
Ciencias > Química > Bioquímica
Ciencias Biomédicas > Biología > Biotecnología
Ciencias Biomédicas > Biología > Biología molecular
Código ID:8092
Depositado:03 Oct 2008 11:03
Última Modificación:06 Feb 2014 07:59

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