3d7 sequence database version 3

Purified AviTag-LILRB1-Fc was biotinylated using BirA biotin-protein ligase (Avidity) (Extended Data Fig. 3a). Red cell ghosts obtained from erythrocytes infected with the LILRB1+ F2 or LILRB1− D11 clone at the schizont-stage were incubated with biotinylated LILRB1-Fc fusion protein and subsequently treated with 0.25 mM 3,3-dithiobis (sulfosuccinimidyl propionate) (DTSSP, Thermo Scientific) to generate crosslinks. Red cell ghosts treated without LILRB1-Fc were used as controls. The red cell ghosts were then washed in phosphate-buffered saline, solubilised by boiling in sample buffer in the absence of 2-mercaptoethanol and immunoprecipitated using streptavidin Sepharose (GE Healthcare). The immunoprecipitated products were eluted using 50 mM dithiothreitol (DTT) and analysed using a liquid chromatography-tandem mass spectrometer (LC-MS/MS, LTQ Orbitrap, Thermo Scientific) after tryptic digestion. All MS/MS spectra data were analysed using Mascot software (Matrix Science) with the 3D7 sequence database version 3 (PlasmoDB, http://plasmodb.org). Proteins detected in control precipitates from F2 and D11 clones and LILRB1-Fc precipitates from D11 clone were considered non-specific (Extended Data Fig. 3b, 3c and Supplementary Table 1).