Solution Structure of a Repeated Unit of the ABA-1 Nematode Polyprotein Allergen of Ascaris Reveals a Novel Fold and Two Discrete Lipid-Binding Sites
Comparison of the fluorescence enhancement of the fatty acid probe, DAUDA, upon binding to recombinant (r)ABA-1A before and after removal of contaminating ligand(s) by reverse phase chromatography. Fluorescence emission spectra of DAUDA (1.39 µM, λexc = 345 nm) upon additions of increasing concentrations of (A) rABA-1A, and (B) RP-ABA-1A, plotted on the same scale for comparison. The inset shows the increase in DAUDA fluorescence intensity at 475 nm with increasing concentrations of (circles) rABA-1A and (black squares) RP-ABA-1A under identical experimental conditions. Estimated KD for DAUDA binding to RP-ABA-1A is 0.11 (±0.03) µM.