Structure-Function Relationship Studies of the Rhodobacter Sphaeroides Cytochrome AA(3)

Cytochrome c oxidases catalyze the reduction of O2 to H 2O and use the redox energy released by this reaction to generate an electrochemical proton gradient. This proton gradient can be used to produce ATP by ATP-Synthase. Rhodobacter sphaeroides cytochrome c oxidase, the focus of this thesis, serves as an excellent model to systematically understand the more complicated mammalian cytochrome c oxidases. The role of a putative proton channel identified in the X-ray crystal structure of the cytochrome c oxidases from bovine heart mitochondria and P. denitrificans has been studied using site-directed mutagenesis coupled with a variety of biophysical characterization methods. Based on the work done, it is concluded that the putative proton channel is not functional in prokaryotic oxidases. A hydrogen bond responsible for a large red shift in the visible spectrum of cytochrome c oxidases compared to that of model heme compounds has been identified and characterized through site-directed mutagenesis and resonance Raman spectroscopy. Residues coordinating the calcium ion in R. sphaeroides cytochrome c oxidase have been mutated to mimic the metal binding site of bovine mitochondrial oxidase. Residues in a putative oxygen channel to the active site have been mutated and characterized. It was observed that only the mutations near the active site hinder oxygen binding.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Lee, Hang Mo

Contributors dc:contributor

• Gennis, Robert B.

• Chemistry, Biochemistry

Language dc:language

eng

Identifier

(MiAaPQ)AAI3017140

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/84025