Spectroscopic Characterization of the Function and Mechanism of Dehaloperoxidase

Abstract

The research presented in this thesis focuses on three main areas of work with dehaloperoxidase, DHP. The development of a viable source of recombinant DHP is discussed first. Enzymatic activity of DHP is the second area of research discussed followed by ligand binding studies. All of this research is done in the attempt to understand the structure function relationship within DHP. DHP's globin structure and peroxidase activity is the source of our interest in studding the structure function relationship in DHP. Typically, globins are not peroxidases. In DHP's case a unique heme active site, that is not common for globins or peroxidases, alters the ligand binding and the Poulos-Kraut push/pull mechanism of compound I formation. Specifically DHP has a distal valine residue that is unable to function as the residue that is responsible for the abstraction of a proton. Typically, the distal residue in both globins and peroxidases is a histidine. The distal histidine is credited with the abstraction of the proton in the pull step of the Poulous-Kraut push/pull mechanism.