Extended Data Fig. 4: Mapping of Fc(aMD4)B3-binding sites on human MetECD.

a, The association between Fc(aMD4)B3 and human MetECD, mouse MetECD, or chimeric MetECD that variably fused human and mouse was evaluated by pull-down assay. PA-tagged MetECD was precipitated using anti-PA tag antibody conjugated beads. Consistent with our previous report that aMD4 peptide binds to human but not mouse MetECD40, Fc(aMD4)B3 bound to human MetECD (hWT) but not to mouse MetECD (mWT). Replacement of the PSI domain and the IPT domains to mouse sequence (variants A–E) preserved the binding to Fc(aMD4)B3, indicating the PSI domain and the IPT domains were dispensable for Fc(aMD4)B3 binding. In contrast, human-specific residues in blades 5–7 of the Sema domain were required for Fc(aMD4)B3 binding (variant F). The numbers in the Sema domain indicate each blade. b, Human-specific residues in blade 6 (B6-1 and B6-2 in d) were indispensable for Fc(aMD4)B3 binding. c, Human-specific residues in blade 5 (B5-1 and B5-2 in d) were also indispensable or contributing for Fc(aMD4)B3 binding, respectively. d, Amino acid sequence alignment of human and mouse Met Sema domains. Residues that are different between human and mouse are indicated in bold. The red bars (B5-1, B6-1, and B6-2) indicate the residues indispensable for Fc(aMD4)B3 binding. The orange bar (B5-2) indicates the residues that contribute to Fc(aMD4)B3 binding.