Figure 3: FRET measurements reveal movements of individual residues during PIP2-induced closure. | Nature Communications

Figure 3: FRET measurements reveal movements of individual residues during PIP2-induced closure.

From: Structural rearrangements underlying ligand-gating in Kir channels

Figure 3

(a) Representative time course of FRET measurements by proteinase K-mediated donor dequenching. KirBac1.1 R151C and T264C tetramers were labelled by A/D mixtures, then reconstituted into liposomes (POPE:POPG=3:1). Proteinase K (0.08U per well) was added after 8 repeated readings (Fo) (T=5 min); Alexa-Fluor-546 emission (F, a.u.) was monitored until emission reached maximum (Fmax). (b) Cα–Cα distance between adjacent subunits of labelled residues predicted by FRET (mean±s.e., n=6–9 in each case) versus those present in the KirBac1.1 (2WLL) crystal structure. R and P values of correlation are 0.51 (P<0.010), 0.54 (P<0.006) for Cα–Cα distances calculated from measured FRET efficiencies in the absence (control) and presence of 1.25% PIP2, respectively.

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