2.A.57.4.1
The parasite plasma membrane equilibrative nucleoside transporter, PfNT1 or PfENT1, of 422 aas and 11 or 12 TMSs in a 6 + 5 TMS arrangement. Both L- and D-nucleosides of both purines and pyrimidines are transported; L-nucleosides are transported with low affinity (transports adenosine, inosine and thymidine (K_M values=1-2mM) (Downie et al., 2006)). ENT1 is the primary uptake transporter for purines, and transmembrane segments 2, 10 and 11 appear to line the purine permeation pathway (Riegelhaupt et al., 2010, Nishtala et al. 2018).  Putative purine nucleoside interacting residues in the malaria parasite purine uptake transporter, PfENT1, are critical for transporter function (Dillague and Akabas 2023).