Dose-response curves showing the effects on parasite growth over 2 complete erythrocytic cycles of control antimalarial compounds chloroquine (CQ) and artesunate, or peptidyl boronic acid compounds 1a and 4c. Calculated EC50 values (in nM for CQ and artesunate, in uM for the boronic acid compounds) and 95% confidence intervals (in parentheses) are shown. The 1AC5 parasite line, which expresses 8-10-fold less PfSUB1 than the B11 line, was ~13-fold more sensitive to inhibitor 4c than the B11 line, whilst the sensitivities of the two lines to the other drugs were similar. All assays were performed in triplicate using different sources of blood in each case. Error bars, S.D.