University of Illinois Urbana-Champaign

Structure and Function Relationships in Cytochrome Bo(3) Oxidase and Cytochrome Bd-I Oxidase From Escherichia Coli

Osborne, Jeffrey P.

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https://hdl.handle.net/2142/84906

Description

Title
Structure and Function Relationships in Cytochrome Bo(3) Oxidase and Cytochrome Bd-I Oxidase From Escherichia Coli
Author(s)
Osborne, Jeffrey P.
Issue Date
1999
Doctoral Committee Chair(s)
Gennis, Robert B.
Department of Study
Biochemistry
Discipline
Biochemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Biophysics, General
Language
eng
Abstract
Structure and function relationships in the two terminal oxidases in Escherichia coli have been investigated. Cytochrome bo3 oxidase, a member of the heme/copper superfamily, is found to have a semiquinone intermediate during turnover of quinol. Additionally, after the quinol is consumed and turnover stops, the enzyme is found in a mixture of oxidation states, one of which is the elusive Peroxy species. No free radical species is observed in conjunction with the Peroxy species. Support for a cytochrome bo3 proton pumping mechanism is presented in which a histidine ligand for CuB dissociates upon reduction. The other terminal oxidase, cytochrome bd-I oxidase, is not related to the heme/copper superfamily and was studied through sequence analyses and ligand reactivity. Sequence analysis suggested conserved residues that were then mutated. Reactivity with ligands indicated that the active site of cytochrome bd is highly unusual in that heme d binds ligands but virtually always remains high-spin, five-coordinate.
Graduation Semester
1999
Type of Resource
text
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http://hdl.handle.net/2142/84906

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