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theses

The enzyme supercomplex Photosystem II (PSII) is the sole water oxidase known to have developed in nature. Accordingly, it is the source of almost all biologically useful reductant present in the biosphere, as well as the molecular oxygen in Earth’s atmosphere. Understanding this massive, complex protein is thus crucial to development of novel bioinspired water-oxidizing catalysts, a crucial step toward reducing dependence on fossil fuels, which are also ultimately products of PSII activity. Improving understanding and control of the operation and regulation of PSII is also critical for development of agriculture, biofuels, and bioproducts.
As the active domains of PSII are highly conserved, substitution of functional and tuning components of the complex and investigation of alterations to functionality represents a well-proven method for study of this complex. However, the development of a range of novel techniques for phenomenological investigation of PSII has allowed for the observation of previously unknown processes and functionalities associated with certain components of PSII. The use of exogenous quinones to remove the kinetic constraint of electron removal from the acceptor side of PSII allows a more accurate determination of the first electron transfer steps within PSII, removing a major confounding variable from kinetic studies of processes within the enzyme. Expansion of fluorometric and oximetric techniques allows processes to be probed under conditions previously inaccessible due to the need to generate specific and often unnatural sample conditions. With these new developments, cofactor substitutions are employed to clarify the functionality of the native cofactors.

ETD_9052

Ph.D.

Includes bibliographical references

by Colin Gates

doi:10.7282/t3-b7b6-2n84

ETD doctoral

The author owns the copyright to this work.