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Abstract
This dissertation includes four chapters. Chapter 1 includes introduction and literature review. Chapter 2 and chapter 3 were submitted papers. Chapter 4 includes conclusions.Chapter 2 of this dissertation describes the application of X-Ray crystallography to obtain the tertiary structure of two interesting mutants of secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus, namely C295A and I86A, along with their substrates and cofactor. The focus of the research is to investigate to central role of Zn2+ in the catalytic action of the enzyme. This helps to solve the ongoing debate about the existence of pentacoordinated zinc in this thermophilic enzyme and the dynamics of all the residues coordinating to this metal ion. This also sheds a light on the role of Glu60 in the catalysis mechanism of Thermoanaerobacter ethanolicus secondary alcohol dehydrogenase.
Chapter 3 of this dissertation describes the discovery of condition to crystallize the recently found carbonyl reductase from a soil bacterium Leifsonia xyli. Applying X-Ray crystallography results in the first structure of this enzyme at high resolution. A docking program was used to dock BTAP, an important pharmaceutical intermediate, as well as either of the two cofactors NAD(H) and NADP(H). This elucidates the catalytic mechanism of Leifsonia xyli carbonyl reductase.