Accordingly, the invention provides constructs in which the nucleic acids encoding Plasmodium falciparum MSP4 and MSP5, and the resulting polypeptides, have been modified. More particularly, this invention provides constructs encoding recombinant MSP4 and MSP5 polypeptides, which are expressed as soluble, secreted polypeptides in a baculovirus-insect cell expression system. It was surprisingly found that the recombinant polypeptides contain an EGF-like domain at the C-terminus that is properly folded in the polypeptide.