Nucleotide binding properties of a P-glycoprotein homologue from Plasmodium falciparum

Abstract

The Plasmodium falciparum P-glycoprotein homologue 1 (PGH1) is structurally similar to several members of the ATPbinding cassette (ABC) superfamily of membrane transporters. We have examined whether the nucleotide binding domains predicted from the deduced amino sequence are functional by photoaffinity labeling of purified parasite digestive vacuoles with the analogue 8-azido-α[32P]ATP (8-N3-ATP). This reagent labels a 160-kDa protein in vacuoles from both a chloroquine sensitive and a chloroquine-resistant parasite isolate. The 160-kDa protein could be immunoprecipitated with affinity-purified antibodies against the P. falciparum P-glycoprotein homologue (PGH1). Inhibition of photoaffinity ..