Direct demonstration of CQ binding to PfCRT was a very important result, but equilibrium binding studies with radio-labeled CQ obviously do not allow for definition of the drug binding site. To answer this question, the Roepe and Wolf laboratories designed and synthesized various CQ photoaffinity probes. One particularly novel probe, haboring both per-fluoro-azido and biotin tags via flexible linkers attached to the aliphatic terminus of CQ, proved to be enormously useful. It has recently led to the identification of the CQ binding site in HB3 isoform PfCRT, and has also quickly quantified relative affinities of other drugs (QN, VPL and so on) versus various PfCRT isoforms [90] . An obvious extension of this work would be the definition of CQ binding-site differences (if any) for other PfCRT isoforms, and perhaps similar studies with PfMDR1.