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. 2015 Oct 28;112(45):13874–13879. doi: 10.1073/pnas.1512994112

Fig. S4.

Fig. S4.

Protein topological rearrangements triggered by changes in PC content in the proteoliposomes. Real-time FRET measurements of proteoliposomes containing LacY and submitted to lipid exchange to trigger addition (A) or dilution (B) of PC. Changes in phospholipid composition were as described in Fig. S2. Lipid exchange was triggered by addition of MβCD-loaded MLVs to proteoliposomes 30 s after stabilization of fluorescence, with kinetics measured at 0.5-s intervals. Red (C6), blue (NT), and magenta (P7) traces indicate Trp-IAEDANS FRET observed with IAEDANS-labeled H205W/V331C, L14W/V331C, and F250W/V331C mutants, respectively. Black traces indicate measurements performed in the absence of lipid exchange as described in Fig. S3. Data represent the normalized FRET expressed as the ratio (F(t) − F0)/(Fmax − F0), as described in SI Methods. The experiments were repeated three to five times, and the data represent mean values ± lower and upper confidence limits from exponential fits of the data. Bar graphs summarized time constants shown in Table S1.