Fig. 2. DMAs bind to the EV71 SLII bulge via an entropically driven mechanism.
a Single-point 1H-13C TROSY HSQC titrations of A(13C)-selectively labeled SLII constructs with the respective DMAs added at fivefold excess. The blue correlation peaks across each spectrum correspond to that of free SLII. The spectra were collected at 900 MHz in 10 mm K2HPO4, 20 mm KCl, 0.5 mm EDTA, and 4 mm BME (pH 6.5) D2O buffer at 298 K. b Calorimetric titrations of DMA-001, DMA-135, and DMA-155 reveal a single transition on the binding isotherm characterized by an entropically favored and enthalpically disfavored molecular recognition event. All titration data were processed and analyzed using Affinimeter25. The processed thermograms were fit to a 1:1 stoichiometric binding model, represented by the red lines. Reported values for dissociation constants (KD) and corresponding standard deviation are from triplicate experiments. Goodness of fit (χ2) of the experimental data to the 1:1 binding model are reported for each titration. The experiments were performed in 10 mm K2HPO4, 20 mm KCl, 0.5 mm EDTA, and 4 mm DTT (pH 6.5) buffer at 298 K. Data represented as mean ±SD of n = 3 experimental replicates. Uncertainties in individual binding isotherms are automatically calculated using Affinimeter and are determined by considering the noise and quality of raw data and the dispersion of the integrated signal as a function of concentration.