Moulin, Martine (2019) Biochemical, biophysical, and structural studies of seed proteins from Moringa oleifera and implications for traditional water purification. Doctoral thesis, Keele University.

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Moringa oleifera is a tropical plant that belongs to the Moringaceae family and is native to northern India. Moringa oleifera is called The Miracle Tree because many of its parts have valuable applications. In particular, seed extracts from the plant have been used in traditional water treatment throughout Africa. The application of this extract to untreated water causes a 95% reduction of turbidity, and a decrease in particle and bacterial content. Numerous laboratories have demonstrated these effects but the precise nature and properties of the active components in the extract has been unclear.
A purified fraction of cationic coagulant proteins from seed extract has been characterised at a molecular level using biochemical and biophysical methods including chromatography, mass spectrometry and tandem mass spectrometry. These studies have allowed the identification of two main isoforms (Mo-CBP3-3 and Mo-CBP3-4) of the Moringa oleifera chitin binding protein Mo-CBP3, (a 2S albumin protein) present in this fraction of interest. The X-ray crystallographic structure of one isoform, Mo-CBP3-4, was determined to a resolution of 1.68 Å. This structure provides detailed information relating to this diverse family of albumins as well as insights for the observed flocculating properties of the protein. Neutron reflection studies of the structure and composition of interfacial layers at the solid/solution interface show that the crude seed extract behaves differently from the purified fraction. These results have been related to the anti-microbial, coagulation and flocculation properties of both the seed extract and the purified fraction and are placed in the context of water purification. Future directions could include the development of a recombinant expression system for large scale production of perdeuterated protein allowing contrast matching studies by neutron reflection and a neutron crystallographic structure to understand the nature of hydration interactions.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Natural Sciences > School of Life Sciences
Contributors: Forsyth, T (Thesis advisor)
Haertlein, Michael (Thesis advisor)
Depositing User: Lisa Bailey
Date Deposited: 18 Mar 2019 10:19
Last Modified: 03 Sep 2020 11:45

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