High-throughput virtual screening for novel dhfr inhibitors of P. Jiroveci from the zinc database.

Many of the opportunistic infections that occur at this late stage can be fatal and since that Pneumocystis carinii pneumonia (PCP) is a leading opportunistic infection found among immunocompromised (CD4 cell < 200) patients worldwide. DHFR is responsible for the growth and maturation of sporozoites stage (life cycle) in Pneumocystis as reported. Currently, 13 million chemical compounds are available for virtual screening in ZINC database. The biological information of four known drug molecules like TMP/SMX, Dapsone, Atovaquone and Pentamidine were collected from the PubChem compound database. Q-Site Finder online tool was used to determine the active site of DHFR in P. jiroveci. LogP values of chemical compounds were identified with the Atom-additive method. Since, existing drugs are synthetic chemicals that give more side effects in Pneumocystis affected patients. Polar surface area value of oxamide (86.18) was predicted to be in the ranges of existing drug values. Pentamidine was proved to be a more efficient ligand based on the dock score of -26.3398 still could not be considered as the natural compound oxamide also was highly comparable with the value of -20.3173. The binding affinity of the selected molecule was analyzed through Pose View and LigPlot.