Date of Graduation

8-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry (PhD)

Degree Level

Graduate

Department

Chemistry & Biochemistry

Advisor/Mentor

Durham, Bill

Committee Member

Koeppe, Roger E. II

Second Committee Member

Millett, Francis S.

Third Committee Member

Stites, Wesley E.

Keywords

Pure sciences; Biological electron transfer; Cytochrome b5; Metalloproteins; Photoreactive complexes; Ruthenium complexes

Abstract

Photoreactive complexes to study the kinetics of electron transfer of proteins have been in use for a long time. It has always been speculated that complexes bind near the heme or the electron transfer reaction would not occur. But it is unkown exactly how the complex interacts with the protein. The structural, thermodynamic, and kinetic properties of rat liver microsomal cytochrome b5 were investigated when bound to ruthenium dimer complexes. Heteronuclear Single Quantum Coherence studies support a dynamic binding model of a dimer Ru complex bound near the protein’s heme involving residues H39, E44, G42, V61, G62, and H63. The enthalpy of binding ΔH was found to be unfavorable: +200 cal/mol, despite a very favorable equilibrium dissociation constant Kd was found to be 40 µM indicating an entropically controlled process. These insights will help with the design of future photoreactive complexes for the study of electron transfer reactions in metalloproteins.

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