The post-translational modification in cytochrome c oxidase is required to establish a functional environment of the catalytic site

Tapan Kanti Das, Catherine Pecoraro, Farol L. Tomson, Robert B. Gennis, Denis L. Rousseau

Research output: Contribution to journalArticle

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Abstract

Mutation of tyrosine-288 to a phenylalanine in cytochrome c oxidase from Rhodobacter sphaeroides drastically alters its properties. Tyr-288 lies in the Cu(B)-cytochrome a3 binuclear catalytic site and forms a hydrogen bond with the hydroxy group on the farnesyl side chain of the heme. In addition, through a post-translational modification, Y288 is covalently linked to one of the histidine ligands that is coordinated to Cu(B). In the Y288F mutant enzyme, the 'as-isolated' preparation is a mixture of reduced cytochrome a and oxidized cytochrome a3. The cytochrome α3 heme, which is largely six- coordinate low-spin in both oxidation states of the mutant, cannot be reduced by cytochrome c, but only by dithionite, possibly due to a large decrease in its reduction potential. It is postulated that the Y288F mutation prevents the post-translational modification from occurring. As a consequence, the catalytic site becomes disrupted. Thus, one role of the post-translational modification is to stabilize the functional catalytic site by maintaining the correct ligands on Cu(B), thereby preventing nonfunctional ligands from coordinating to the heme.

Original languageEnglish (US)
Pages (from-to)14471-14476
Number of pages6
JournalBiochemistry
Volume37
Issue number41
DOIs
StatePublished - Oct 13 1998

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Cytochromes a3
Electron Transport Complex IV
Post Translational Protein Processing
Heme
Catalytic Domain
Ligands
Cytochromes a
Dithionite
Rhodobacter sphaeroides
Mutation
Cytochromes
Cytochromes c
Phenylalanine
Histidine
Tyrosine
Hydrogen
Hydrogen bonds
Oxidation
Enzymes

ASJC Scopus subject areas

  • Biochemistry

Cite this

The post-translational modification in cytochrome c oxidase is required to establish a functional environment of the catalytic site. / Das, Tapan Kanti; Pecoraro, Catherine; Tomson, Farol L.; Gennis, Robert B.; Rousseau, Denis L.

In: Biochemistry, Vol. 37, No. 41, 13.10.1998, p. 14471-14476.

Research output: Contribution to journalArticle

Das, Tapan Kanti ; Pecoraro, Catherine ; Tomson, Farol L. ; Gennis, Robert B. ; Rousseau, Denis L. / The post-translational modification in cytochrome c oxidase is required to establish a functional environment of the catalytic site. In: Biochemistry. 1998 ; Vol. 37, No. 41. pp. 14471-14476.
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