Biolayer interferometry analysis of the B.tauACE2 ectodomain binding to the HKU5-33s RBDs. Binding avidities were determined by steady-state kinetics and are reported as apparent affinities (KD,app). In (E)-(H), the vertical dotted lines indicate the transition between association and dissociation phases. One representative out of two biological replicates with independently produced batches of proteins is shown for (E)-(H).