Purification and characterization of human-derived Pneumocystis jirovecii dihydrofolate reductase expressed in Sf21 insect cells and in Escherichia coli.

Pneumonia caused by Pneumocystis jirovecii is still a major opportunistic infection among patients with AIDS. This opportunitistic pathogen is susceptible to therapy with inhibitors of the enzyme dihydrofolate reductase (DHFR) that target cell growth. Recent studies have shown that recombinant human-derived Pneumocystis DHFR (pDHFR) differs from rat-derived pDHFR by 38% in amino acid sequence.