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Título:
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One single salt bridge explains the different cytolytic activities shown by actinoporins sticholysin I and II from the venom of Stichodactyla helianthus
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Autores:
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Rivera de Torre, Esperanza ;
Palacios Ortega, Juan ;
García Linares, Sara ;
Gavilanes, José G. ;
Martínez del Pozo, Álvaro
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Tipo de documento:
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texto impreso
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Editorial:
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Elsevier, 2017-12
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/restrictedAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Química: Bioquímica
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Tipo = Artículo
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Resumen:
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Sticholysins I and II (StnI and StnII), ?-pore forming toxins from the sea anemone Stichodactyla helianthus, are water-soluble toxic proteins which upon interaction with lipid membranes of specific composition bind to the bilayer, extend and insert their N-terminal ?-helix, and become oligomeric integral membrane structures. The result is a pore that leads to cell death by osmotic shock. StnI and StnII show 93% of sequence identity, but also different membrane pore-forming activities. The hydrophobicity profile along the first 18 residues revealed differences which were canceled by substituting StnI amino acids 2 and 9. Accordingly, the StnID9A mutant, and the corresponding StnIE2AD9A variant, showed enhanced hemolytic activity. They also revealed a key role for an exposed salt bridge between Asp9 and Lys68. This interaction is not possible in StnII but appears conserved in the other two well-characterized actinoporins, equinatoxin II and fragaceatoxin C. The StnII mutant A8D showed that this single replacement was enough to transform StnII into a version with impaired pore-forming activity. Overall, the results show the key importance of this salt bridge linking the N-terminal stretch to the ?-sandwich core. A conclusion of general application for the understanding of salt bridges role in protein design, folding and stability.
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En línea:
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https://eprints.ucm.es/45632/1/1-s2.0-S000398611730632X-main.pdf
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