Fig. 3: Selection of spike-protein-binding FNAPs via multivalent SELEX.
a, Progress in spike-binding selection for multivalent (medusa) and monovalently prefocused (monovalent) selection strategies. Bulk affinity of trivalent and monovalent FNAP libraries to trimeric spike protein was assessed by quantifying the amount of FNAPs in the flow-through (FT) versus elution fractions. b, Increase in bulk affinity of trimeric FNAP libraries to spike protein by comparing the MEDUSA assemblies prepared with the FNAP library from selection round 1 versus selection round 7 for both selection strategies using mass photometry. c, Progression of selection process indicated by the decrease in FNAP library complexity using NGS. Data are presented as mean ± s.d. (n = 2, independent sequencing runs). d, Multiple sequence alignment of the top sequences from NGS data for two tested selection strategies with corresponding sequence abundances. The common motif of sequences retrieved from the monovalent selection process is displayed as a nested graph. e, Enrichment of three selected hits over the rounds of selection for two tested selection strategies using NGS. f, Sequences and side-chain structures of selected FNAPs. xxx, scaffold-hybridization region.
