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oai:docta.ucm.es:20.500.14352/528562024-09-23T17:52:34Zcom_20.500.14352_14col_20.500.14352_15

Infrared spectroscopy study on the conformational changes leading to pore formation of the toxin Sticholysin II Alegre Cebollada, Jorge Martínez Del Pozo, Álvaro Gavilanes, José G. Goormaghtigh, Erik Sea anemone Actinoporin Toxin Infrared Bioquímica (Química) The structure of the actinoporin sticholysin II (StnII) in the pore state was investigated by Fourier transform infrared spectroscopy in the attenuated total reflection configuration. 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/cholesterol unilamellar vesicles were employed. The a-helix content increases in;30% upon lipid binding, which agrees with an extension of eight or nine residues at the N-terminal helix. Furthermore, analyses of dichroic spectra show that the extended N-terminal helix would have a 31º tilt with respect to the membrane normal. The orientation of the central beta-sandwich was also estimated. In addition, it was detected that StnII alters the orientation of the lipid acyl chains. 1H/2Hexchange experiments sustain a mainly superficial interaction between StnII and the membrane, with no protection of the beta-sandwich. The implications of the results in the mechanism of pore formation are discussed. Depto. de Bioquímica y Biología Molecular Fac. de Ciencias Químicas TRUE pub 2023-06-20T12:56:43Z 2023-06-20T12:56:43Z 2007-11 journal article https://hdl.handle.net/20.500.14352/52856 1542-0086 10.1529/biophysj.106.102566 spa open access application/pdf