Fig. 2: Structural basis of RIFIN binding to KIR2DL1.
From: RIFINs displayed on malaria-infected erythrocytes bind KIR2DL1 and KIR2DS1
a, Phylogenetic analysis of KIR2DL1-binding RIFINs from two Thai field-isolated strains (red squares, Lek79; yellow circles, Lek174) and the 3D7 KIR2DL1 binders (pink highlight). b, Phylogenetic analyses of RIFINs from pfKE01 (left) or pfSE01 (right) and the KIR2DL1-binding RIFINs from 3D7 (pink highlight). Triangles indicate RIFINs predicted to bind to KIR2DL1, and stars indicate the candidates tested by SPR analysis in c. c, SPR analysis of the binding of KIR2DL1-binding RIFIN from pfKE01 and pfSN01 to KIR2DL1 and LILRB1. Affinities calculated by equilibrium fitting from at least three independent experiments (Prism 10) are denoted within each box, if applicable. d, Crystal structures of complexes of KIR2DL1 (green) with RBK21 (light pink) or KEN-01 (dark pink). The right-hand panel shows the overlay of these two complexes aligned on KIR2DL1. The lower right inset shows KIR2DL1 (green) bound to MHC class I, HLA-Cw4 (orange and teal) (Protein Data Bank (PDB) 1IM9). e, Interfaces between RBK21 (left) or KEN-01 (right) and KIR2DL1, showing interfacial residues. f, Experiments comparing binding (SPR, left) and folding (circular dichroism (CD), right) of wild-type (WT) RBK21 and its S221R mutant. For SPR, twofold dilutions from 20 µM to 39 nM of either WT or S221R RBK21 were flowed over the immobilized KIR2DL1. The same RBK21 variants were tested for correct folding by comparison by means of CD spectroscopy.
