Fig. 1: High-affinity binding of H1 to ProTα is independent of fluorescence labeling. | Nature Communications

Fig. 1: High-affinity binding of H1 to ProTα is independent of fluorescence labeling.

From: Polyelectrolyte interactions enable rapid association and dissociation in high-affinity disordered protein complexes

Fig. 1

a Illustration of the highly dynamic and intrinsically disordered protein complex between ProTα (red) and H1 (blue) with snapshots from coarse-grained MD simulations12. b Transfer efficiency histograms of 50 pM ProTα E56C/D110C labeled with Alexa Fluor 488/594 in the presence of increasing concentrations of unlabeled H1 at 200 mM ionic strength, fit globally with two Gaussian peak functions for the unbound (red) and bound (purple) ProTα populations, respectively (sum: black lines). c Transfer efficiency histograms from a competition experiment with constant concentrations of 50 pM labeled ProTα and 10 nM unlabeled H1, and increasing concentration of unlabeled ProTα as indicated in the panels. d Resulting fractions of bound labeled ProTα as a function of the total concentration of H1 (left panel, b) and unlabeled ProTα (right panel, c). The global fit of the two datasets (continuous line, see “Methods” for details) results in an affinity of H1 for fluorophore-labeled ProTα of (0.73 ± 0.07) nM and for unlabeled ProTα of (1.1 ± 0.4) nM (s.d. calculated from at least three independent repeats).

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