Show simple item record

dc.contributor.authorMahboob, Abdullah
dc.date.accessioned2014-10-01T14:11:37Z
dc.date.available2014-10-01T14:11:37Z
dc.date.issued2014-10-01
dc.identifier.urihttp://hdl.handle.net/10464/5755
dc.description.abstractABSTRACT Photosystem II (PSII) of oxygenic photosynthesis has the unique ability to photochemically oxidize water, extracting electrons from water to result in the evolution of oxygen gas while depositing these electrons to the rest of the photosynthetic machinery which in turn reduces CO2 to carbohydrate molecules acting as fuel for the cell. Unfortunately, native PSII is unstable and not suitable to be used in industrial applications. Consequently, there is a need to reverse-engineer the water oxidation photochemical reactions of PSII using solution-stable proteins. But what does it take to reverse-engineer PSII’s reactions? PSII has the pigment with the highest oxidation potential in nature known as P680. The high oxidation of P680 is in fact the driving force for water oxidation. P680 is made up of a chlorophyll a dimer embedded inside the relatively hydrophobic transmembrane environment of PSII. In this thesis, the electrostatic factors contributing to the high oxidation potential of P680 are described. PSII oxidizes water in a specialized metal cluster known as the Oxygen Evolving Complex (OEC). The pathways that water can take to enter the relatively hydrophobic region of PSII are described as well. A previous attempt to reverse engineer PSII’s reactions using the protein scaffold of E. coli’s Bacterioferritin (BFR) existed. The oxidation potential of the pigment used for the BFR ‘reaction centre’ was measured and the protein effects calculated in a similar fashion to how P680 potentials were calculated in PSII. The BFR-RC’s pigment oxidation potential was found to be 0.57 V, too low to oxidize water or tyrosine like PSII. We suggest that the observed tyrosine oxidation in BRF-RC could be driven by the ZnCe6 di-cation. In order to increase the efficiency of iii tyrosine oxidation, and ultimately oxidize water, the first potential of ZnCe6 would have to attain a value in excess of 0.8 V. The results were used to develop a second generation of BFR-RC using a high oxidation pigment. The hypervalent phosphorous porphyrin forms a radical pair that can be observed using Transient Electron Paramagnetic Resonance (TR-EPR). Finally, the results from this thesis are discussed in light of the development of solar fuel producing systems.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectphotochemically oxidize wateren_US
dc.subjectPhotosystem II (PSII)en_US
dc.subjectElectrostatic factors contributing to the high oxidation potential of P680en_US
dc.subjectTransient Electron Paramagnetic Resonance (TR-EPR)en_US
dc.titleTowards reverse engineering of Photosystem II: Synergistic Computational and Experimental Approachesen_US
dc.typeElectronic Thesis or Dissertationen_US
dc.degree.namePh.D. Biotechnologyen_US
dc.degree.levelDoctoralen_US
dc.contributor.departmentCentre for Biotechnologyen_US
dc.degree.disciplineFaculty of Mathematics and Scienceen_US
dc.embargo.termsNoneen_US
refterms.dateFOA2021-08-04T02:55:22Z


Files in this item

Thumbnail
Name:
Brock_MAHBOOB_Abdullah_2014.pdf
Size:
4.075Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record