The druggable antimalarial target PfDXR : overproduction strategies and kinetic characterization

Show simple item record Goble, Jessica L. Johnson, Hailey De Ridder, Jaco Stephens, Linda L. Louw, Abraham Izak Blatch, Gregory L. Boshoff, Aileen 2014-04-01T09:54:42Z 2014-04-01T09:54:42Z 2013
dc.description.abstract Plasmodium falciparum 1–deoxy–D–xylulose–5–phosphate reductoisomerase (PfDXR) is a key enzyme in the synthesis of isoprenoids in the malaria parasite, using a pathway that is absent in the human host. This enzyme is receiving attention as it has been validated as a promising drug target. However, an impediment to the characterisation of this enzyme has been the inability to obtain sufficient quantities of the enzyme in a soluble and functional form. The expression of PfDXR from the codon harmonised coding region, under conditions of strongly controlled transcription and induction, resulted in a yield of 2 – 4 mg/L of enzyme, which is 8 to 10–fold higher than previously reported yields. The kinetic parameters Km, Vmax and kcat were determined for PfDXR using an NADPH–dependent assay. Residues K295 and K297, unique to species of Plasmodium and located in the catalytic hatch region; and residues V114 and N115, essential for NADPH binding, were mutated to resemble those found in E. coli DXR. Interestingly, these mutations decreased the substrate affinity of PfDXR to values resembling that of E. coli DXR. PfDXR-K295N, K297S and PfDXR-V114A, N115G demonstrated a decreased ability to turnover substrate by 4–fold and 2-fold respectively in comparison to PfDXR. This study indicates a difference in the role of the catalytic hatch in capturing substrate by species of Plasmodium. The results of this study could contribute to the development of inhibitors of PfDXR. en_US
dc.description.librarian hb2014 en_US
dc.description.sponsorship National Research Foundation Grant awarded to AB (Thuthuka Programme) and a SAMI Grant awarded to GLB. LSS was awarded a post–doctoral bursary by the South African Malaria Initiative programme; JG was awarded a PhD bursary by SAMI and National Research Foundation and HJ was awarded an Honours bursary by Rhodes University. en_US
dc.description.uri en_US
dc.identifier.citation Goble, JL, Johnson, H, De Ridder, J, Stephens, LL, Louw, A, Blatch, GL & Boshoff, A 2013, 'The druggable antimalarial target PfDXR : overproduction strategies and kinetic characterization', Protein and Peptide Letters, vol. 20, no. 2, pp.115-124. en_US
dc.identifier.issn 0929-8665 (print)
dc.identifier.issn 1875-5305 (online)
dc.language.iso en en_US
dc.publisher Bentham Science Publisher en_US
dc.rights Bentham Science Publishers en_US
dc.subject Plasmodium falciparum en_US
dc.subject DXR en_US
dc.subject Anti–malarial en_US
dc.subject Heterologous expression en_US
dc.subject Molecular chaperones en_US
dc.title The druggable antimalarial target PfDXR : overproduction strategies and kinetic characterization en_US
dc.type Preprint Article en_US

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