Elongation factor Tu (EF-Tu) is encoded by the tuf gene of the plastid organelle of the malaria parasite Plasmodium falciparum. A range of structurally unrelated inhibitors of this GTP-dependent translation factor was shown to have antimalarial activity in blood cultures. The most active was the cyclic-thiazolyl peptide amythiamicin A with an IC50 = 0.01 mu M. Demonstrable complexes were formed in vitro between a recombinant version of P. falciparum EF-Tu(pl) and inhibitors that bind to different sites on EF-Tu; these included the antibiotics kirromycin, GE2270A and enacyloxin IIa.