Fig. 4: The hTNAP^18–500-scFv complex.

a The cryo-EM map for hTNAP-scFv complex viewed at two angles. The electron density map of TNAP dimer was colored in blue and the electron density map of scFv was colored in green. b The cartoon representation of the TNAP-scFv complex, where the dimeric TNAPs were colored in yellow and blue for protomer A and B, respectively, with two scFv molecules in green. c The epitope mapping on hTNAP^18–500. The protomer B was shown as calculated solvent-accessible electrostatic surface-potential maps and the interacting residues from scFv was shown as stick model colored by elements. The critical residues mediating scFv binding were indicated with red frames. d The scFv and scFv-Fc (JTALP001) antibody could increase the alkaline phosphatase activities of hTNAP^18–500 protein. optical density (OD). n = 3 biologically independent samples. e The scFv-Fc (JTALP001) antibody showed varing effect of hTNAP^18–500 mutants on alkaline phosphatase activities. The mutants of hTNAP^18–500 protein were overexpressed in HEK293T and the phosphatase activities in the cell media were measured and calibrated with the expression level as determined by the Western blotting. n = 4 biologically independent samples. All data in this figure are represented as mean ± SD. One-way ANOVA with Tukey’s multiple comparisons test for (e). All experiments were repeated three times independently with similar results. Source data are provided as a Source Data file.