Fig. 2

Lipid binding experiments. a wt-P2 (black) and P2-F57A (red) initial vesicle aggregation profiles as a function of protein concentration. b Decrease in the turbidity signal over time in the mutant sample. c Co-sedimentation at 1:100 P/L (10 μM protein with 1 mM DMPC:DMPG) suggests roughly 50% binding of protein to vesicles. 1, molecular weight marker; 2, wt-P2 in pellet; 3, P2-F57A in pellet; 4, wt-P2 supernatant; 5, P2-F57A supernatant. d Co-sedimentation of wt-P2 with lipid vesicles. 1–2, supernatant and pellet of 20 μM P2 with 1 mM DMPC:DMPG; 3–4 supernatant and pellet of 20 μM P2 with 1 mM DOPC:DOPS. The asterisks indicate the positions of monomeric (*), dimeric (**), and trimeric (***) P2 in the proteolipid pellet. e DSC measurements show the diminished effect of the F57A mutant (red) on the lipid phase transition behaviour, while wt-P2 (black) has a clear effect. Dotted line: lipids alone, dashed line: P/L 1:200, solid line P/L 1:100. f Examples of SPR sensorgrams; shown are duplicate injections of 10 μM wt-P2 (black) and P2-F57A (red) onto immobilized DOPC:DOPS (1:1). g The steady-state affinity of the F57A mutants to DOPC:DOPS (1:1) vesicles is marginally weaker compared to wild type. All error bars are standard deviations