Cytochromec oxidase inParacoccus denitrificans. Protein,chemical, structural,and evolutionary aspects |
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Authors: | Gerhard Buse Guy C M Steffens |
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Institution: | (1) Institut für Biochemie, Rheinisch-Westfälische Technische Hochschule Aachen, Klinikum Pauwelsstr. 30, D-5100 Aachen, Germany |
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Abstract: | Preparations and protein chemical characterizations performed with cytochromec oxidase (E.C. 1.9.3.1) from the purple bacteriumParacoccus denitrificans are reviewed. The simplest catalytically competent complex of the enzyme consists of two subunits of 62012 and 27999 Da. The theoretical hemea/protein ratio of the purified enzyme is 22.0 nmol/mg. The amino acid sequences of both proteins are compared with examples of subunits I and II of mitochondrial terminal oxidases from the main kingdoms of eukaryotes. The significance of the emerging conserved features such as membrane penetration patterns, invariant residues, stoichiometry, and sites of prosthetic groups are discussed. TheParacoccus enzyme represents the only prokaryotic oxidase detailed so far, which is directly related to the mitochondrial oxidases by common ancestry in the growing O2 atmosphere. |
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Keywords: | Cytochromec oxidase membrane protein preparation endosymbiosis purple bacteria mitochondrial origin metal analysis proteinmetal stoichiometry O2 atmosphere 16s rRNA phylogeny |
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