Extended Data Fig. 1: Biophysical characterization of the variable and constant regions of RIFIN, and the RIFIN–LILRB1 complex.
From: Structural basis for RIFIN-mediated activation of LILRB1 in malaria
a, Schematic showing the domain architecture of RIFIN, using numbering from PF3D7_1254800, and surface plasmon resonance analysis of the binding of the constant and variable regions of PF3D7_1254800 to immobilized LILRB1. The variable region was injected in a twofold dilution series from 4 μM to 3.9 nM, while a single injection of 4 μM was used for the constant region. Equilibrium fitting gave Kd = 570 ± 130 nM. Red dotted lines show the fitting to a one-to-one kinetic binding model and give Kd = 1.13 μM, ka = 2.63 × 105 M−1 s−1 and kd = 0.297 s−1 (χ2 = 3.88 RU2) with n = 1 for each series. b, Size-exclusion chromatograms and Coomassie-stained SDS–PAGE gel showing the LILRB1 ectodomain, RIFIN 1254800 variable region and their complex, and a circular dichroism spectrum of RIFIN. c, Size-exclusion chromatogram, Coomassie-stained SDS–PAGE gel and circular dichroism spectrum of the RIFIN 1254800 constant region. d, Size-exclusion chromatogram, Coomassie-stained SDS–PAGE gel and circular dichroism spectrum of the PF3D7_1254800 RIFIN(C223S) mutant. e, Size-exclusion chromatogram, Coomassie-stained SDS–PAGE gel and circular dichroism spectrum of the PF3D7_1254800 RIFIN(C223S/G234R) mutant. Circular dichroism data are the average of 10 technical replicates; size-exclusion chromatograms and gels are from single experiments.
