Fig. 3: Specific interaction of MERS-RBD, HKU4-RBD with hDPP4, TpDPP4, and dcDPP4.

a Characterization of binding affinity of MERS-RBD, HKU4-RBD with hDPP4, TpDPP4, and dcDPP4 by flow cytometry. HEK293T cells expressing various DPP4s were detected by the Alexa Fluor 647 channel. MERS-RBD, HKU4-RBD were detected by FITC channel. b Characterizing interaction of MERS-RBD-Fc-His, HKU4-RBD-Fc-His with hDPP4, TpDPP4, dcDPP4 by co-IP assays. DPP4s were expressed as monomer or homodimer. Images are representative of three independent experiments. Uncropped blots in Source Data are provided as Source Data file. c Interaction between various combinations of RBD and DPP4 characterized by SPR assay with Biacore X100. The binding profiles were shown in the form of sensorgram with gradient concentrations of DPP4 proteins.