Figure 3
HSQC data of Gal-3 in complex with KSDS. 1H–15N HSQC spectra of 15N-enriched Gal-3 FL alone (20 μM, peaks in black) and in the presence of desulfated KSDS at 1 μM (A) and 2 μM (B) are shown. Solution conditions are 20 mM KPhos, pH 6.9, 30 °C. The chemical shift map (∆δ vs. amino acid sequence) for the binding of KSDS to Gal-3 FL is shown in (C), and that for the binding of KSDS to Gal-3 CRD is shown in (D). Horizontal black lines indicate 1SD above the average value. (E) Residues most perturbed by binding of Gal-3 CRD to KSDS are highlighted in red (2 SD above the average ∆δ value) and orange (1 SD above the average ∆δ value) on the structure of the Gal-3 CRD (PDB 1A3K), as discussed in the text. A lactose molecule associated to the canonical contact region of the CRD is shown in blue. (E) The average ∆δ values from Gal-3 FL and Gal-3 CRD HSQC spectra are plotted vs. the KSDS concentration (μM). Solid lines show exponential fits to these data.
