Student Number : 9605361W -
PhD thesis -
School of Pathology -
Faculty of Science / Malaria is one of the most debilitating parasitic infections to have afflicted humanity
and remains an expanding health risk for many countries. This is attributed largely to
the complexity of the parasite’s life cycle and refined ability to evade host immunity.
During development within the erythrocyte, Plasmodium falciparum induces a wide
array of changes to the ultrastructure, function and antigenic properties of the host
membrane. Numerous proteins encoded by the parasite associate with the
erythrocyte skeleton and appear to be essential for P. falciparum survival. The
elucidation of new protein-protein interactions has therefore formed a key area of
malaria research.
To circumvent the difficulties provided by conventional protein techniques, a novel
application of phage display technology was used in this research. P. falciparum
phage display libraries were created and biopanned against human erythrocyte
skeletal protein 4.1 (4.1R). DNA sequencing and bioinformatic investigations
uncovered a number of parasite proteins with binding specificity toward 4.1R. They
included five hypothetical proteins, two invasion proteins, namely erythrocyte binding
antigen-175 (EBA-175) and EBA-181, two predicted protein kinases and a putative
aminopeptidase. A common binding motif displaying homology to muscle myosin
and neurofilament sequences was also identified in four of the ten proteins.
The interaction between EBA-181 and 4.1R was characterised further by mapping
the domain in 4.1R responsible for binding to the parasite protein. Recombinant
proteins were used in blot-overlay and pull-down experiments, which revealed
specific interaction between the highly conserved 10kDa domain and the 4.1R
binding region in EBA-181. Binding was concentration dependent, as well as
saturable and was abolished by heat denaturation of 4.1R.
Functions of the 4.1R-specific parasite proteins remain to be determined, however,
they are potentially involved in parasite growth and survival during intra-erythrocytic
development. Furthermore, these proteins may also participate in the entry and/or
exit of parasites from the human erythrocyte. The interaction of EBA-181 with the 10kDa domain of 4.1R provides new insight into the molecular mechanisms utilised
by P. falciparum during erythrocyte entry. It also highlights the multifunctional role of
malaria invasion proteins, which may contribute to the success of the pathogenic
stage of the parasite’s life cycle.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/2146 |
| Date | 28 February 2007 |
| Creators | Lanzillotti, Roberto |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 14420 bytes, 10535 bytes, 43788 bytes, 132159 bytes, 1542895 bytes, 110879 bytes, 582143 bytes, 435772 bytes, 13754 bytes, 76736 bytes, 13952 bytes, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf |
Page generated in 0.0026 seconds