Small angle scattering studies of chromatin proteins in the human malarial parasite

• Main Author: Jordan, Ashley
• Published: Keele University 2017
• Subjects: 570; R Medicine (General)
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.733268

This thesis describes the biochemical, biophysical and structural characterisation of two proteins believed to play an important role in active gene silencing mechanisms present in the human malarial parasite, Plasmodium falciparum. These investigations were performed using the histone deacetylase enzyme, PfSir2a, and the DNA binding protein, PfAlba3. The initial goal of this PhD project was to obtain structural information on both PfSir2a and PfAlba3, as well as the proposed silencing complex thought to be formed by the two proteins. This information would then aid the development of novel pharmaceuticals with a perspective towards new therapeutics to combat the continued threat of malaria. Thorough biochemical and biophysical characterisation of both PfSir2a and PfAlba3 was conducted and is described in Chapter 3 of the thesis. These results could not characterise a strong interaction between PfSir2a and PfAlba3 and highlighted several properties exhibited by the proteins that, as a result, proved challenging to characterise by structural methods. Most notably concentration dependent oligomerisation and protein aggregation effects were observed for PfSir2a and PfAlba3 respectively. Nevertheless, structural studies were performed using SAXS and SANS techniques to investigate the individual proteins to obtain structural information about the solution state of PfSir2a and PfAlba3 and generate ab initio models for both proteins and these are presented in Chapter 4. The difficulties presented by the target proteins aided in the development of a new investigative method for bio-SANS experiments, SEC-SANS, and the first example of testing and validation of this technique is presented in Chapter 5. The findings of work conducted for this thesis are summarised in Chapter 6 with an outlook for future work and development.