Journal: Biochimica et biophysica acta

Article Title: Lipid and phase specificity of α-toxin from S. aureus.

doi: 10.1016/j.bbamem.2013.04.005

Figure Lengend Snippet: Fig. 5. Role of fluidity for Hla–SM interaction. Liposomes containing 40% cholesterol and variable fractions of two types of sphingomyelin (17 μM in the outer leaflet) were incubated for 40 s or 45 min at 20 °C or 37 °C with 4 μM pyrene labelled Hla. The rest of the lipid consists of ePE and bPS in a ratio of 1: 1. Panel A: Relative excimer fluorescence as obtained for pseudo-ternary and pseudo-binary mixtures (10, 20 and 40% SM with 40% cholesterol and 1: 1 ePE/bPS) and binary mixtures (60% SM with 40% cholesterol, indicated by a star). Samples were diluted to 0.1 μM directly before measurement. Bars indicated liposomes containing eSM, symbols (squares, triangles, circles, diamond) represent liposomes containing OSM as Hla-binding lipid. For comparison, fluorescence levels measured in absence of liposomes (“toxin”) are depicted. After incubation, aliquots of the samples were subjected to 10% SDS–PAGE without heating. A gel showing part of the samples (45 min, 37 °C) is depicted in panel B; the numbers represent the fraction of oligomers based on a densitometric analysis (Quantity One, Bio-Rad, München, Germany). The results for all samples are depicted in panel C, with bars indicating liposomes containing eSM and symbols indicating liposomes containing OSM. Incubation time and temperature was as given in the legend. Marker: Precision Plus Protein unstained Standards (Bio-Rad, München, Germany).

Article Snippet: Marker: Precision Plus Protein unstained Standards (Bio-Rad, 0.037 s−1 and 0.108 s−1) but the overall oligomerisation level is similar for 4 °C, 22 °C and 37 °C.

Techniques: Liposomes, Incubation, Binding Assay, Comparison, SDS Page, Marker