The effects of lipids on the structure of the eukaryotic cytolysin equinatoxin II: A synchrotron radiation circular dichroism spectroscopic study
Andrew J Miles, Alison Drechsler, Katarina Kristan, Gregor Anderluh, Raymond S Norton, BA Wallace, Frances Separovic
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES | ELSEVIER SCIENCE BV | Published : 2008
Synchrotron radiation circular dichroism (SRCD) spectroscopy studies of the eukaryotic pore-forming protein equinatoxin II (EqtII) were carried out in solution and in the presence of micelles or small unilamellar vesicles (SUV) of different lipid composition. The SRCD structural data was correlated with calcein leakage from SUV and with partitioning of EqtII to liposomes, and micelles, according to haemolysis assays. The structure of EqtII in water and dodecylphosphocholine micelles as determined by SRCD was similar to the values calculated from crystal and solution structures of the protein, and no changes were observed with the addition of sphingomyelin (SM). SM is required to trigger pore..View full abstract
Supported by grants from the BBSRC to BAW, Slovenian Research Agency to GA, Australian Research Council to FS, and by a beamtime grant from the CCLRC to FS and a CCLRC joint programme mode access grant to BAW and R.W. Janes (Queen Mary, Univ. of London). RSN is supported by a fellowship from the Australian National Health and Medical Research Council.