Figure 4. Collisional quenching of Trp fluorescence by acrylamide reveals greater accessibility of viral proteins to the quencher in the presence of RC-101.

Stern-Volmer plots for HIV-1 proteins (2 μM) - Nef, protease, and IN – in the absence (open circles) and in the presence of 5-fold molar excess of RC-101 (solid circles). X-axes are molar concentrations of the quencher (acrylamide), Y-axes – ratio of the Trp fluorescence in the absence of the quencher (F₀) and in its presence (F). Dynamic Stern-Volmer coefficients (K_SV) are provided for Nef protein. In contrast, quenching of protease and IN proteins show both strong dynamic and static components reflected in a characteristic upward curvature of Stern-Volmer plots. For these proteins, apparent Stern-Volmer coefficients (K_app) at acrylamide concentration equal 1 M are shown. Increased K_SV (or K_app) in the presence of RC-101 imply higher accessibility of Trp residue(s) to the quencher. Asterisk indicates statistically significant difference (P<0.05).