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Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)

Bibliography: leaves 48-53.

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Main Author: Mtwisha, Linda
Other Authors: Brandt, W B
Format: Thesis
Language:English
Published: Department of Molecular and Cell Biology 2014
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access_status_str Open Access
author Mtwisha, Linda
author2 Brandt, W B
author_browse Brandt, W B
Mtwisha, Linda
author_facet Brandt, W B
Mtwisha, Linda
author_sort Mtwisha, Linda
collection Thesis
description Bibliography: leaves 48-53.
format Thesis
id oai:open.uct.ac.za:11427/9685
institution University of Cape Town (South Africa)
language eng
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license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2014
publishDateRange 2014
publishDateSort 2014
publisher Department of Molecular and Cell Biology
publisherStr Department of Molecular and Cell Biology
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/9685 Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae) Mtwisha, Linda Brandt, W B Lindsey, George G Biochemistry Bibliography: leaves 48-53. LEA proteins are plant proteins that are characteristically hydrophilic and soluble at elevated temperature. The consistent correlation between desiccation tolerance in orthodox seed tissue and an accumulation of LEA proteins suggests that these proteins play an important role in protecting cells from desiccation induced damage. Yeast (Saccharomyces cerevisiae) has been known to desiccate as part of its normal growth cycle and to remain viable after long periods in the desiccated state. As a result of these properties this project was designed to investigate the presence of LEA-like proteins in yeast. A protein was isolated from baker’s yeast that fulfils the requirements for being a LEA protein. This protein, with a molecular mass of 11 kDa, was found to be the most prevalent heat soluble protein in the yeast extract. Antibodies raised against LEA group I proteins recognised this 11 kDa yeast protein in the total extract but failed to recognise the protein after heat treatment at 80°C for 10 min. Amino acid analysis showed that the ll kDa protein was highly hydrophilic - a characteristic of LEA proteins. The protein was partially sequenced (10 cycles) after CNBr digestion and the sequence obtained was compared with the sequence of known proteins in the Stanford databank. Only one protein, HSP 12, was identified to be 100 % homologous to the obtained sequence without the introduction of gaps. Despite a previous report that HSP 12 is a heat shock protein, HSP 12 was present in a reduced concentration in yeast grown at 37 °C compared with yeast grown at 30 °C. HSP 12 was found to increase in concentration after entry into stationary phase - a time when nutrients are limiting and the yeast is preparing to reduce its water content and sporulate. This might be considered equivalent to plant seed maturation - the stage when LEA proteins are synthesised. Moreover, growth conditions that have been reported to stimulate LEA protein biosynthesis in plants also stimulated HSP 12 synthesis in yeast. Purified HSP 12 was shown to inhibit thermal denaturation of yeast alcohol dehydrogenase (ADH) at elevated temperatures. This is a functional property of the pea seed p11 LEA group I protein. From the above results, it was therefore concluded that HSP 12 should be identified as a LEA-like protein rather than as a heat shock protein. 2014-11-16T20:02:37Z 2014-11-16T20:02:37Z 1998 Master Thesis Masters MSc http://hdl.handle.net/11427/9685 eng application/pdf Department of Molecular and Cell Biology Faculty of Science University of Cape Town
spellingShingle Biochemistry
Mtwisha, Linda
Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)
thesis_degree_str Master's
title Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)
title_full Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)
title_fullStr Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)
title_full_unstemmed Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)
title_short Isolation and characterisation of a LEA-like protein from yeast (Saccharomyces cerevisiae)
title_sort isolation and characterisation of a lea like protein from yeast saccharomyces cerevisiae
topic Biochemistry
url http://hdl.handle.net/11427/9685
work_keys_str_mv AT mtwishalinda isolationandcharacterisationofalealikeproteinfromyeastsaccharomycescerevisiae