DFT study of a substrate and inhibitors of 1-deoxy-2-xylulose-5-phosphate reductoisomerase – the potential novel target molecule for anti-malaria drug development

1-Deoxy-2-xylulose-5-phosphate (DOXP) reductoisomerase is a novel target for developing anti-malaria drugs. The determination of structural and electronic properties of the inhibitor molecules is of crucial importance for analyzing the interactions between DOXP-reductoisomerase and its inhibitors. Geometry-optimizations and single point calculations at the B3LYP/3-21G*//B3LYP/3-21G** and B3LYP/3-21G*//MP2/3-21G** levels were performed to determine the structures and charge distributions of an enzyme substrate (1-deoxy-D-xylulose 5-phosphate) and the two inhibitors (fosmidomycin and FR-900098). The theoretically derived bond lengths are in excellent agreement with the corresponding experimental values reported for similar structures. Partial charges and dipole moments are assigned using the Mulliken and natural population analyses. The calculated structures and partial charge distributions can readily be used for the further development of biologically active inhibitors of DOXP-reductoisomerase as well as parameters for docking experiments.Electronic Supplementary Material available.     

Exported plasmodial J domain protein,PFE0055c,and PfHsp70-x form a specific co-chaperone-chaperone partnership

Plasmodium falciparum is a unicellular protozoan parasite and causative agent of a severe form of malaria in humans, accounting for very high worldwide fatality rates. At the molecular level, survival of the parasite within the human host is mediated by P. falciparum heat shock proteins (PfHsps) that provide protection during febrile episodes. The ATP-dependent chaperone activity of Hsp70 relies on the co-chaperone J domain protein (JDP), with which it forms a chaperone-co-chaperone complex. The exported P. falciparum JDP (PfJDP), PFA0660w, has been shown to stimulate the ATPase activity of the exported chaperone, PfHsp70-x. Furthermore, PFA0660w has been shown to associate with another exported PfJDP, PFE0055c, and PfHsp70-x in J-dots, highly mobile structures found in the infected erythrocyte cytosol. Therefore, the present study aims to conduct a structural and functional characterization of the full-length exported PfJDP, PFE0055c. Recombinant PFE0055c was successfully expressed and purified and found to stimulate the basal ATPase activity of PfHsp70-x to a greater extent than PFA0660w but, like PFA0660w, did not significantly stimulate the basal ATPase activity of human Hsp70. Small-molecule inhibition assays were conducted to determine the effect of known inhibitors of JDPs (chalcone, C86) and Hsp70 (benzothiazole rhodacyanines, JG231 and JG98) on the basal and PFE0055c-stimulated ATPase activity of PfHsp70-x. In this study, JG231 and JG98 were found to inhibit both the basal and PFE0055c-stimulated ATPase activity of PfHsp70-x. C86 only inhibited the PFE0055c-stimulated ATPase activity of PfHsp70-x, consistent with PFE0055c binding to PfHsp70-x through its J domain. This research has provided further insight into the molecular basis of the interaction between these exported plasmodial chaperones, which could inform future antimalarial drug discovery studies.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12192-020-01181-2.