- Title
- A Comparison of Mitochondrial Heat Shock Protein 70 and Hsp70 Escort Protein 1 Orthologues from Trypanosoma brucei and Homo sapiens
- Creator
- Hand, Francis Bryan
- ThesisAdvisor
- Boshoff, Aileen
- Subject
- Trypanosoma brucei
- Subject
- Heat shock proteins
- Subject
- Molecular chaperones
- Subject
- Transport protein
- Subject
- AlphaFold
- Subject
- Mitochondrial heat shock protein
- Date
- 2023-03-29
- Type
- Academic theses
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10962/422281
- Identifier
- vital:71927
- Description
- The causative agent of African trypanosomiasis, Trypanosoma brucei (T. brucei), has an expanded retinue of specialized heat shock proteins, which have been identified as crucial to the progression of the disease. These play a central role in disease progression and transmission through their involvement in cell-cycle pathways which bring about cell-cycle arrest and differentiation. Hsp70 proteins are essential for the maintenance of proteostasis in the cell. Mitochondrial Hsp70 (mtHsp70) is a highly conserved molecular chaperone required for both the translocation of nuclear encoded proteins across the two mitochondrial membranes and the subsequent folding of proteins in the matrix. The T. brucei genome encodes three copies of mtHsp70 which are 100% identical. MtHsp70 self-aggregates, a property unique to this isoform, and an Hsp70 escort protein (Hep1) is required to maintain the molecular chaperone in a soluble, functional state. This study aimed to compare the solubilizing interaction of Hep1 from T. brucei and Homo sapiens (H. sapien). The recently introduced Alphafold program was used to analyze the structures of mtHsp70 and Hep1 proteins and allowed observations of structures unavailable to other modelling techniques. The GVFEV motif found in the ATPase domain of mtHsp70s interacted with the linker region, resulting in aggregation, the Alphafold models produced indicated that the replacement of the lysine (K) residue within the KTFEV motif of DnaK (prokaryotic Hsp70) with Glycine (G), may abrogate bond formation between the motif and a region between lobe I and II of the ATPase domain. This may facilitate the aggregation reaction of mtHsp70 orthologues and provides a residue of interest for future studies. Both TbHep1 and HsHep1 reduced the thermal aggregation of TbmtHsp70 and mortalin (H. sapien mtHsp70) respectively, however, TbHep1 was ~ 15 % less effective than HsHep1 at higher concentrations (4 uM). TbHep1 itself appeared to be aggregation-prone when under conditions of thermal stress, Alphafold models suggest this may be due to an N-terminal α- helical structure not present in HsHep1. These results indicate that TbHep1 is functionally similar to HsHep1, however, the orthologue may operate in a unique manner which requires further investigation.
- Description
- Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2023
- Format
- computer, online resource, application/pdf, 1 online resource (146 pages), pdf
- Publisher
- Rhodes University, Faculty of Science, Biotechnology Innovation Centre
- Language
- English
- Rights
- Hand, Francis Bryan
- Rights
- Use of this resource is governed by the terms and conditions of the Creative Commons "Attribution-NonCommercial-ShareAlike" License (http://creativecommons.org/licenses/by-nc-sa/2.0/)
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | HAND-MSC-TR23-69.pdf | 4 MB | Adobe Acrobat PDF | View Details Download |