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Titolo:
Effect of pH on the conformation, interaction with membranes and hemolyticactivity of sticholysin II, a pore forming cytolysin from the sea anemone Stichodactyla helianthus
Autore:
Alvarez, C; Pazos, IF; Lanio, ME; Martinez, D; Schreier, S; Casallanovo, F; Campos, AM; Lissi, E;
Indirizzi:
Univ Santiago Chile, Fac Chem & Biol, Dept Chem, Santiago 33, Chile Univ Santiago Chile Santiago Chile 33 iol, Dept Chem, Santiago 33, Chile Univ Havana, Fac Biol, Dept Biochem, Havana, Cuba Univ Havana Havana Cuba iv Havana, Fac Biol, Dept Biochem, Havana, Cuba Univ Sao Paulo, BR-05508 Sao Paulo, Brazil Univ Sao Paulo Sao Paulo Brazil BR-05508 ulo, BR-05508 Sao Paulo, Brazil
Titolo Testata:
TOXICON
fascicolo: 4, volume: 39, anno: 2001,
pagine: 539 - 553
SICI:
0041-0101(200104)39:4<539:EOPOTC>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTINIA-EQUINA L; PROTEIN CYTOLYSIN; LIPID-MEMBRANES; FLUORESCENCE; MECHANISM; TOXINS; SPECTROSCOPY; INTERMEDIATE; TRYPTOPHAN; RADICALS;
Keywords:
sticholysin II; hemolytic activity; pH; conformational changes; membrane binding;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Lissi, E Univ Santiago Chile, Fac Chem & Biol, Dept Chem, POB 40, Santiago33, Chile Univ Santiago Chile POB 40 Santiago Chile 33 Santiago 33, Chile
Citazione:
C. Alvarez et al., "Effect of pH on the conformation, interaction with membranes and hemolyticactivity of sticholysin II, a pore forming cytolysin from the sea anemone Stichodactyla helianthus", TOXICON, 39(4), 2001, pp. 539-553

Abstract

Sticholysin II (St II) is a pore forming cytolysin obtained from the sea anemone Stichodactyla helianthus. Incubation of diluted St II solutions at different pHs (ranging from 2.0 to 12) slightly changes the secondary structure of the protein. These changes are particularly manifested at high pH. Similarly, the intrinsic fluorescence of the protein indicates a progressiveopening of the protein structure when the pH increases from acidic (2.0) to basic (12). These modifications are only partially reversible and do not produce any significant increase in the small capacity of the protein to bind hydrophobic dyes (ANS or Prodan). Experiments carried out with model membranes show a reduced capacity of binding to egg phosphatidyl choline:sphingomyelin (1:1) liposomes both at low (2.3) and high (11.5) pH. Preincubation of the protein in the 2.5-9.0 pH range does not modify its hemolytic activity, measured in human red blood cells at pH 7.4. On the other hand, preincubation at pH 11.5 drastically reduces the hemolytic activity of the toxin. This strong reduction takes place without measurable modification of the toxin ability to be adsorbed to the red blood cell surface. This indicates that preincubation at high pH irreversibly reduces the capacity of the toxin to form pores without a significant decrease in its binding capacity. Thepresent results suggest that at pH greater than or equal to 10 St II experiences irreversible conformational changes that notably reduce its biological activity. This reduced biological activity is associated with a partial defolding of the protein, which seems to contradict what is expected in terms of a molten globule formalism. (C) 2000 Elsevier Science Ltd. All rightsreserved.

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Documento generato il 19/01/20 alle ore 09:11:45