Fig. 3: Api m 1/nanobody interactions and functional impact.
a Interactions of the AM1-1 complementarity determining region 3 (CDR3) (green) with residues of the catalytic network (yellow) and residues involved in Ca2+ binding (purple) of Api m 1 (orange). Hydrogen bonds are shown as dotted lines. b Phospholipase activity assay of Api m 1 in the presence of the nanobodies. Activity was measured as fluorescence using the phospolipase A2 substrate Red/Green BODIPY®PC-A2. Data are presented as mean of duplicates. Source data are provided as a Source Data file. c Cartoon representation of the nanobody AM1-4 (blue) in complex with a dimer of Api m 1 (orange). d Allergen-induced activation of effector cells was assessed with RBL-SX38 cells expressing the human FcεRI receptor. The effector cells were sensitized with nb-hIgE. Degranulation was induced by nApi m 1 and measured as released Beta-Hexosaminidase activity. Data are presented as mean of duplicates. Source data are provided as a Source Data file. e Cartoon representation of a single molecule of Api m 1 (orange) from the dimer complex. The calcium-binding loop (purple) and the glycosylation site (N13) with the first N-acetylglucosamine (GlcNAc) (cyan) are highlighted. f Superposition of a Api m 1 molecule (orange) from the binary complex with the Api m 1 molecule (gray) and nanobody AM1-1 (green) from the ternary complex. Bound AM1-1 sterically clashes with parts of the N-terminal loop and the glycan linked to N13.
