11-13 November 2019
Africa/Johannesburg timezone
SA-ESRF Light Source Conference

Biophysical characterization of Plasmodium falciparum Hsp70-Hsp90 organizing protein (PfHop) reveals a monomer that is characterised by folded segments connected by flexible linkers

13 Nov 2019, 12:15
Gold Room

Gold Room

Oral BioScience Parallel-Bio


Dr Stanley Makumre (University of Venda)


Plasmodium falciparum causes the most lethal form of malaria. The cooperation of heat shock protein (Hsp) 70 and 90 is important for the folding of a select number of cellular proteins that are crucial for cyto-protection and development of the parasites. Hsp70 and Hsp90 are brought into a functional complex that allows substrate exchange by stress-inducible protein 1 (STI1), also known as Hsp70-Hsp90 organizing protein (Hop). P. falciparum Hop (PfHop) co-localizes and occurs in complex with the parasite cytosolic chaperones, PfHsp70-1 and PfHsp90. Here, we characterized the structure of recombinant PfHop using synchrotron radiation circular dichroism (SRCD) and small-angle X-ray scattering. Structurally, PfHop is a monomeric, elongated but folded protein, in agreement with its predicted TPR domain structure. Using SRCD, we established that PfHop is unstable at temperatures higher than 40 °C. This suggests that PfHop is less stable at elevated temperatures compared to its functional partner, PfHsp70-1, that is reportedly stable at temperatures as high as 80 °C. These findings contribute to our understanding of the role of the Hop-mediated functional partnership between Hsp70 and Hsp90.

Primary author

Dr Stanley Makumre (University of Venda)


Prof. Addmore Shonhai (University of Venda) Prof. Inari Kursula (University of Bergen) Dr Juha Vahokoski (University of Bergen) Dr Tawanda Zininga (University of Venda)

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