The human immunodeficiency virus, (HIV-1), pandemic: cellular therapies, stem cells and biobanking.

The Human Immunodeficiency Virus, (HIV-1), has become a major global health threat with recent estimates suggesting that 68% of people living with HIV (PLWH) reside in Sub-Saharan Africa. The current strategies for containment of this disease in the absence of an effective vaccine are of concern in terms of long-term fiscal sustainability and cost effectiveness. HIV prevalence rates are set to rise, not because of increasing incidence but rather because of the effort involved in implementing the anti-retroviral (ARV) programmes, especially on the African continent.

The druggable antimalarial target PfDXR: overproduction strategies and kinetic characterization.

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.

Screening for small molecule modulators of Hsp70 chaperone activity using protein aggregation suppression assays: inhibition of the plasmodial chaperone PfHsp70-1.

Plasmodium falciparum heat shock protein 70 (PfHsp70-1) is thought to play an essential role in parasite survival and virulence in the human host, making it a potential antimalarial drug target. A malate dehydrogenase based aggregation suppression assay was adapted for the screening of small molecule modulators of Hsp70. A number of small molecules of natural (marine prenylated alkaloids and terrestrial plant naphthoquinones) and related synthetic origin were screened for their effects on the protein aggregation suppression activity of purified recombinant PfHsp70-1.

Co-expression of the Plasmodium falciparum molecular chaperone, PfHsp70, improves the heterologous production of the antimalarial drug target GTP cyclohydrolase I, PfGCHI.

Molecular chaperones have been used for the improved expression of target proteins within heterologous systems; however, the chaperone and target protein have seldom been matched in terms of origin. We have developed a heterologous co-expression system that allows independent expression of the plasmodial chaperone, PfHsp70, and a plasmodial target protein. In this study, the target was Plasmodium falciparum GTP cyclohydrolase I (PfGCHI), the first enzyme in the plasmodial folate pathway.

Plasmodium falciparum encodes a single cytosolic type I Hsp40 that functionally interacts with Hsp70 and is upregulated by heat shock.

Heat shock protein 70 (Hsp70) and heat shock protein 40 (Hsp40) function as molecular chaperones during the folding and trafficking of proteins within most cell types. However, the Hsp70-Hsp40 chaperone partnerships within the malaria parasite, Plasmodium falciparum, have not been elucidated. Only one of the 43 P.

The malarial drug target Plasmodium falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase (PfDXR): development of a 3-D model for identification of novel, structural and functional features and for inhibitor screening.

A three-dimensional model of the malarial drug target protein PfDXR was generated, and validated using structure-checking programs and protein docking studies. Structural and functional features unique to PfDXR were identified using the model and comparative sequence analyses with apicomplexan and non-apicomplexan DXR proteins. Furthermore, we have used the model to develop an efficient approach to screen for potential tool compounds for use in the rational design of novel DXR inhibitors.

The TPR2B domain of the Hsp70/Hsp90 organizing protein (Hop) may contribute towards its dimerization.

The role of the TPR2B domain of Hop is as yet unknown. We have shown here by site directed mutagenesis and size exclusion chromatography for the first time that the TPR1 and TPR2B domains of Hop independently dimerized, and that the dimerization of TPR2B was not dependent on its predicted two-carboxylate clamp residues. Furthermore, our data indicated that the dimerization of Hop and its domains was not disrupted in the presence of Hsp70 and Hsp90 peptides.

The Agrobacterium tumefaciens DnaK: ATPase cycle, oligomeric state and chaperone properties.

DnaK is a molecular chaperone that promotes cell survival during stress by preventing protein misfolding. The chaperone activity is regulated by nucleotide binding and hydrolysis events in the N-terminal ATPase domain, which in turn mediate substrate binding and release in the C-terminal substrate binding domain. In this study we determined that ATP hydrolysis was the rate limiting step in the ATPase cycle of Agrobacterium tumefaciens DnaK (Agt DnaK); however the data suggested that Agt DnaK had a significantly lower affinity for ATP than Escherichia coli DnaK.