A new type of high affinity folic acid transporter in the protozoan parasite Leishmania and deletion of its gene in methotrexate resistant cells

摘要: Abstract The protozoan parasite Leishmania is a folate auxotroph and thus depends on the uptake of from environment to meet its requirement. We show here thatLeishmania contains several putative pteridine transporter genes. Some these genes are deleted in methotrexate-resistantLeishmania cells where there no measurable methotrexate. Transport studies suggest that has more than one active transporter, these, named FT5, corresponds very high affinity (K m 84 nm). both methotrexate was impaired an FT5 null mutant at low substrate concentrations (50 nm), although transport properties higher (1000 nm) were not statistically different between wild-type mutant. Modulation expression also changes susceptibility These results have permitted characterization novel class transporters gene products possibly transporting folates related molecules under varying conditions.