Fig. 1: The P. falciparum proteins directly interact with the human pentameric IgM core.

a Schematics of the domain organizations of VAR2CSA, TM284VAR1, DBLMSP, and DBLMSP2. Black lines indicate the protein fragments that are recombinantly produced for cryo-EM study, whereas red arrows indicate the regions that are structurally modeled into the density maps. Domain numbers are used to indicate DBL subclasses rather than positions in the gene in the recent nomenclature system^55,56. For example, VAR2CSA domains are now referred to as DBLpam1–DBLpam2–CIDRpam–DBLpam3–DBLεpam4–DBLεpam5–DBLε10, whereas TM284VAR1 domains are DBLα1.8–CIDRβ2–DBLγ7–DBLε11–DBLζ2–DBLε6. Nevertheless, old naming schemes are still adopted in this paper, since they were widely used in the previous literature. NTS N-terminal sequence, ID interdomain, TM transmembrane, ATS acidic terminal sequence, CIDR cysteine-rich interdomain region. b SPR analyses of the interactions between the P. falciparum proteins and Fcμ–J, performed by passing purified Fcμ–J (from 40 nM to 2.5 nM indicated with different colors) to immobilized P. falciparum proteins. All SPR experiments in this paper have been repeated at least two times with similar results.