FIG 5.
SLA80 and εA(pεA)19 compete for the same binding site on dengue virus NS5. (A) Fluorescence titrations of εA(pεA)19 with DENV3 NS5 (λex = 325 nm; λem = 410 nm) in standard buffer (100 mM NaCl, 50 mM Tris [pH 7.5], and 10% glycerol at 10°C) in the absence and presence of DENV3 SLA80 at two concentrations, 8.0 × 10−7 M and 2.5 × 10−6 M. The concentration of εA(pεA)19 is 8.0 × 10−7 M. The solid lines are nonlinear least-squares fits of the titration curve with a K of 2.2 × 106 M−1 (no SLA80), a K of 7.0 × 106 M−1 (0.8 μM SLA80), and a K of 7.5 × 106 M−1 (2.5 μM SLA80). (B) Fluorescence titrations of εA(pεA)19 with DENV3 NS5 (λex = 325 nm; λem = 410 nm) in the absence and presence of DENV2 SLA80 at two concentrations, 8 × 10−7 M and 2.5 × 10−6 M. The solid lines are nonlinear least-squares fits of the titration curve with a K of 2.2 × 106 M−1 (no SLA80), a KSLA80 of 1.0 × 107 M−1 (0.8 μM SLA80), and a KSLA80 of 1.2 × 107 M−1 (2.5 μM SLA80).