Makhoba, X. H. | Search bioRxiv

bioRxiv2023

The Computational Analysis of Plasmodium falciparum Heat Shock Proteins Reveals an Interplay with Polyamines

The current drugs available in the market are not effective due to growing numbers of resistance to the causative agent of malaria. There are various Plasmodium parasites, of which Plasmodium falciparum is the main cause of morbidity and mortality reported worldwide. Therefore, there is an urgent need to come up with an innovative and effective treatment for this disease. Polyamines play a major role in the parasites well-being and growth, while heat shock proteins keep the proteomics of the parasite in good shape. In this study, In Silico analysis of the interaction between putrescine, spermidine, spermine, and heat shock proteins was carried out to establish the binding site for drug discovery. Computational tools such as Bioedit, PROCHECK, KNIME Hub, and Schrodinger were used. The results revealed interactions between polyamines and heat shock proteins with glutamine and aspartic acid being common amino acids where interaction occurs between the chaperones and polyamines. MD shows a strong interaction between PfHsp70-1 and putrescine, but the best interaction is observed for PfHsp70-1 and spermidine. Based on these results, a follow-up study will be conducted to establish the synthesis of drugs that will be used as targets for both polyamines and heat shock proteins to eradicate malaria. Authors summaryThe emanation and spread of Plasmodium parasites that are resistant to antimalarial therapy is one of the main problems in the treatment of malaria. This is a result of the Plasmodium parasites ongoing evolution and the creation of novel strategies for surviving drug toxicity. Studies of antimalarial drug development have been focused on polyamine biosynthesis by targeting precursors such as ornithine decarboxylase, adenosylmethionine decarboxylase, and spermidine synthase and protein-protein interactions between Plasmodium falciparum chaperones spotting out Hsp90, Hsp70, and Hsp40 as potential targets with little attention being paid to the interaction between polyamines and molecular chaperones. Therefore, to study these interactions the binding sites of all 3D structures were identified using SiteMap, and a docking was performed using the Schrodinger software with OPLS4 force field and XP.

bioinformatics↗

bioRxiv2020

Comparative characterisation of Plasmodium falciparum Hsp70-1 relative to E. coli DnaK reveals functional specificity of the parasite chaperone

Hsp70 is one of the most prominent molecular chaperones. Although Hsp70s from various organisms are generally conserved, they exhibit specialised cellular functions. It remains to be fully understood how these highly conserved molecules exhibit specialised functional features. Plasmodium falciparum Hsp70-1 (PfHsp70-1) is a cytosol localised molecular chaperone that is implicated in the cyto-protection and pathogenicity of the malaria parasite. In the current study, we investigated the comparative structure-function features of PfHsp70-1 relative to its homologue, E. coli Hsp70 (DnaK) and a chimeric protein, KPf, that was constituted by the ATPase domain of DnaK and the substrate binding domain (SBD) of PfHsp70-1. Recombinant forms of all the three Hsp70s exhibited similar secondary and tertiary structural fold. We further established that compared to DnaK, both KPf and PfHsp70-1 were more stable to heat stress and exhibited higher basal ATPase activity. A recombinant P. falciparum Hsp40 (PfHsp40) stimulated the ATPase activities of all the three Hsp70s. In addition, both PfHsp70-1 and KPf exhibited preference for asparagine rich peptides as opposed to DnaK. Furthermore, all the three proteins exhibited self-association capabilities in vitro. Recombinant P. falciparum adenosylmethionine decarboxylase (PfAdoMetDC) co-expressed in E. coli with either KPf or PfHsp70-1 was produced as a fully folded product. On the other hand, co-expression of PfAdoMetDC with heterologous DnaK in E. coli did not promote folding of the former. These findings demonstrated that the SBD of PfHsp70-1 regulates several functional features of the protein and that this molecular chaperone is tailored to facilitate folding of plasmodial proteins.

biochemistry↗