title: Overexpression, Purification and Characterisation of the Plasmodium falciparum Hsp70-z (PfHsp70-z) Protein.
abstract: Six Hsp70-like genes are represented on the genome of Plasmodium falciparum. Of these two occur in the cytosol: P. falciparum Hsp70-z (PfHsp70-z) and PfHsp70-1. PfHsp70-1 is a well characterised canonical Hsp70 that facilitates protein quality control and is crucial for the development of malaria parasites. There is very little known about PfHsp70-z. However, PfHsp70-z is known to be essential and is implicated in suppressing aggregation of asparagine-rich proteins of P. falciparum. In addition, its expression at the clinical stage of malaria correlates with disease prognosis. Based on structural evidence PfHsp70-z belongs to the Hsp110 family of proteins. Since Hsp110 proteins have been described as nucleotide exchange factors (NEFs) of their canonical Hsp70 counterparts, it has been speculated that PfHsp70-z may serve as a NEF of PfHsp70-1. In the current study, P. falciparum cells cultured in vitro were subjected to heat stress, triggering the enhanced expression of PfHsp70-z. Biochemical assays conducted using recombinant PfHsp70-z protein demonstrated that the protein is heat stable and possesses ATPase activity. Furthermore, we observed that PfHsp70-z is capable of self-association. The structural-functional features of PfHsp70-z provide further evidence for its role as a chaperone and possible nucleotide exchange factor of PfHsp70-1.
authors.affiliation: Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, 0950, South Africa.
authors.forename: Tawanda
authors.initials: T
authors.lastname: Zininga
authors.affiliation: Protein Structure-Function Research Unit, School of Molecular & Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa.
authors.forename: Ikechukwu
authors.initials: I
authors.lastname: Achilonu
authors.affiliation: Department of Biochemistry, Microbiology & Biotechnology, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Hoppe
authors.affiliation: Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa.
authors.forename: Earl
authors.initials: E
authors.lastname: Prinsloo
authors.affiliation: Protein Structure-Function Research Unit, School of Molecular & Cell Biology, University of the Witwatersrand, Johannesburg 2050, South Africa.
authors.forename: Heini W
authors.initials: HW
authors.lastname: Dirr
authors.affiliation: Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, 0950, South Africa.
authors.forename: Addmore
authors.initials: A
authors.lastname: Shonhai
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D018869:Heat-Shock Response; D010963:Plasmodium falciparum / Q000235:genetics*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D018840:HSP70 Heat-Shock Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases