and FC(F)(F)c1ccc2nnc(CNC(=O)c3ccc4C(=O)N5CCCCCC5=Nc4c3)n2c1). For N, we used full-length nucleocapsid (see Supporting Information Section 4.2.2), and used nanobodies developed to bind to the N-and C-terminal domains. A total of 119 compounds were analyzed in 8-point and 12-point dilution assays between 45 nM and 100 µM. However, it was found that N would show a drop in normalized fluorescence intensity F norm upon the addition of 1-5% of DMSO (dimethylsulfoxide, see also Figure ), likely due to slow polymerization and sedimentation of N over time. This made it impossible to determine K D values, and the assay development had to be abandoned.