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dc.contributor.advisorWilbanks, Sigurd
dc.contributor.authorRenshaw, Jessica
dc.date.available2015-08-23T20:57:07Z
dc.date.copyright2015
dc.identifier.citationRenshaw, J. (2015). A probing tail of our molecular chaperones (Thesis, Master of Science). University of Otago. Retrieved from http://hdl.handle.net/10523/5846en
dc.identifier.urihttp://hdl.handle.net/10523/5846
dc.description.abstractMolecular chaperone proteins play a pivotal role in maintaining normal proteostasis within the cell by aiding the correct folding of nascent chains. Understanding how these proteins function, has implications for a milieu of human diseases. Here the structures of Hsc70 from two different species (bovine and porcine), are analysed. These proteins differ by one amino acid in the nucleotide binding domain, M93V (bovine to porcine) and by four residues in the C-terminus, where there is an additional GGXP motif in bovine Hsc70 protein. Small angled X-ray scattering on native Hsc70 found that these proteins varied in their overall size, in both ATP- and ADP-bound conditions. These results indicated that the C-terminus is important for the overall structure and function of Hsc70 protein. The alternate isoform of Hsc70, Hsc54, has a deletion of residues 464 - 616, resulting in an incomplete SBD, the C-terminus however is still retained. In an effort to glean more information about the C-terminus a recombinant clone of Hsc54 was constructed, along with a bacterial expression cell line that does not contain the Hsc70 prokaryotic homolog protein, DnaK. Recombinant Hsc54 was successfully purified and small angled X-ray scattering studies were undertaken. These results when amalgamated together identified the C-terminal tail of Hsc70 as an important unfolded protein domain. The small angled X-ray scattering models showed that the GGXP motif influenced the overall compactness of Hsc70 protein. Circular dichroism experiments on chemically synthesised C-terminal tail peptides revealed a temperature-dependent conformational change; a random coil conformation to a poly proline type II helical structure. These results gave rise to a thermal switch hypothesis, whereby upon heat shock the C-terminal domain of Hsc70 transitions from a largely unstructured domain to a loose helical structure, preventing co-chaperones from binding. Leaving the co-chaperones available to bind to the inducible Hsp70 chaperones, which do not contain any GGXP motifs in their C-terminal domain.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectmolecular
dc.subjectchaperones
dc.subjectprotein
dc.subjectsmall
dc.subjectangled
dc.subjectx-ray
dc.subjectscattering
dc.subjectcirular
dc.subjectdichroism
dc.subjectrecombinant
dc.subjectnative
dc.titleA probing tail of our molecular chaperones
dc.typeThesis
dc.date.updated2015-08-23T07:10:55Z
dc.language.rfc3066en
thesis.degree.disciplineBiochemistry
thesis.degree.nameMaster of Science
thesis.degree.grantorUniversity of Otago
thesis.degree.levelMasters
otago.openaccessOpen
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