The N-terminal helical motif is a structured region that contributes to potency. A) Sequence, predicted secondary structure, and conservation of C-furSema (based on an alignment of human, rat, mouse, cow, dog, chicken, and zebrafish orthologs). B) ΔN-C-furSema, a N-terminal helical deletion decreases the potency of C-furSema (IC50 = 111 ± 21 nM vs. 25 ± 3 nM, respectively). C) Difference CD spectrum of dimeric versus monomeric C-furSema reveals a characteristic loss in α-helical content. (Inset) CD spectra of dimeric C-furSema (dashed line) and C-furSema3Mon (solid line).