Biochemistry, Biophysics, and Structural Biology Commons^™

Mechanisms Of Chloroperoxidases-Catalyzed Enantioselective Transformations From Spectroscopic And X-Ray Crystallographic Studies Of Enzyme-Substrate Complexes, Xiaoqing Tang

FIU Electronic Theses and Dissertations

The chloroperoxidase secreted from Caldariomyces fumago catalyzes broad spectrum of reactions. The crystallography combined with X-ray diffraction analysis was conducted to reveal recombinant CPO expressed in a modified Aspergillus niger system. Our results indicated that despite functional similarities with wild type CPO, recombinant CPO is over glycosylated with more mannose. Besides, ten iodide ion binding sites were identified in rCPO and six of them were found to be well superimposed on previously reported structure of the wild type CPO. Therefore, recombinant CPO shares almost the same structure with wild type CPO, and the Aspergillus niger is a potential system for …

Investigating The Role Of The Proximal Cysteine Hydrogen Bonding Network And Distal Pocket In Chloroperoxidase, Elwood Kwong Lam

FIU Electronic Theses and Dissertations

Chloroperoxidase (CPO) is one of the most versatile heme enzyme isolated from the marine fungus, Caldariomyces fumago. Functionally, CPO can catalyze four types of reactions: peroxidation (peroxidase-like), dismutation (catalase-like), halogenation (halogenase-like), and peroxygenation (P450-like). Structurally, CPO has a distal and proximal pockets that can be best described as a hybrid of classical peroxidase and P450s. As a heme-thiolate protein, CPO contains the conserved proximal Pro28-Cys29-Pro30 stretch found in other members of the family. However, the structural and functional roles of these proline residues remain poorly understood. Site-directed mutagenesis was undertaken to generates three CPO mutants, P28A-, P30A-, P28A/P30A-CPO. The replacement …

Enzyme Catalyzed And Ultrasound Assisted Transformation Of Selected Pollutants, Yi Tan

FIU Electronic Theses and Dissertations

The widespread use of synthetic drugs and as feed additives has resulted in the release of large amounts of biologically active chemicals into the environment. Exposure to environmentally relevant concentrations of chemicals can have severe effects on human health. Therefore, effective degradation of these synthetic, biologically active compounds is of paramount importance.

Diphenhydramine (DPH) has been selected as a target compound for ultrasound remediation. The results demonstrated that ultrasound-induced degradation has potential applications in managing aqueous media contaminated with DPH.

Atorvastatin and roxarsone have been selected as representative substrates for chloroperoxidase (CPO) catalyzed transformation of pollutants. These studies demonstrate atorvastatin …

The Influence Of The Proximal Thiolate Ligand And Hydrogen Bond Network Of The Proximal Helix On The Structural And Biochemical Properties Of Chloroperoxidase, Elena Shersher

FIU Electronic Theses and Dissertations

Chloroperoxidase (CPO) from Caldariomyces fumago is a versatile heme enzyme with great potential for environmental and pharmaceutical applications. It catalyzes a plethora of reactions including halogenation, dismutation, epoxidation, and oxidation. The diverse catalytic capabilities of CPO have long been attributed to the protein’s distinct active site that combines structural features of peroxidases and cytochromes P450. Particularly, the role of the axial thiolate ligand in CPO catalysis has been much debated. Furthermore, no data are available on the role of hydrogen bonding between Arg 26-Asn 37 and Ala 27-Asn 33 of the proximal helix in defining the structural and catalytic properties …

Nuclear Magnetic Resonance Spectroscopic And Computational Investigations Of Chloroperoxidase Catalyzed Regio- And Enantio-Selective Transformations, Rui Zhang

FIU Electronic Theses and Dissertations

Chloroperoxidase (CPO) is the most versatile heme-containing enzyme that catalyzes a broad spectrum of reactions. The remarkable feature of this enzyme is the high regio- and enantio-selectivity exhibited in CPO-catalyzed oxidation reactions. The aim of this dissertation is to elucidate the structural basis for regio- and enantio-selective transformations and investigate the application of CPO in biodegradation of synthetic dyes.

To unravel the mechanism of CPO-catalyzed regioselective oxidation of indole, the dissertation explored the structure of CPO-indole complex using paramagnetic relaxation and molecular modeling. The distances between the protons of indole and the heme iron revealed that the pyrrole ring of …