Fig. 3: Stapling and lipidation confer superior biophysical and antiviral properties independently and in combination.
a AlphaScreen assay demonstrating the binding activity of RQ-01, and its analogs lacking either the lipid or the linker-lipid combination, for its target, the 5-helix bundle (5-HB) of SARS-CoV-2 comprised of 3 HR1 and 2 HR2 domains. Data are mean ± SEM for assays performed in technical quadruplicate and then repeated with similar results. IC50 values were calculated by nonlinear regression analysis of the dose-response curves. b The comparative antiviral activity of the same trio of compounds was tested in infectivity assays using Omicron variant B.1.1.529.2 pseudovirus in ACE2-expressing HEK293T cells. Data are mean ± SEM for assays performed in technical quadruplicate and then repeated with similar results. IC50 values were calculated by nonlinear regression analysis of the dose-response curves. c–e RQ-01 (lipidated/stapled) and SARSHRC-PEG4-chol (SP4C) (lipidated/not stapled) were evaluated in infectivity assays using pseudoviruses B.1.617.2 (c) and B.1.1.529.1 (d) and the live Delta (B.1.617.2) virus (e). Data are mean ± SEM for assays performed in technical quadruplicate (PV) or triplicate (LV) and then repeated with similar results. IC50 values were calculated by nonlinear regression analysis of the dose-response curves. f–h The comparative stability of RQ-01 and SARSHRC-PEG4-chol (SP4C) upon exposure to acid, base, and extreme heat (80 °C) was assessed by HPLC-based detection and quantitation. Data are mean ± SEM for assays performed in technical quadruplicate and then repeated with similar results.
