Protein chaperones mediating copper insertion into the Cu-A site of the aa(3)-type cytochrome c oxidase of Paracoccus denitrificans

作者：Dash Banaja Priyadarshini; Alles Melanie; Bundschuh Freya Alena; Richter Oliver M H; Ludwig Bernd^*

来源：Biochimica et Biophysica Acta-Bioenergetics, 2015, 1847(2): 202-211.

DOI：10.1016/j.bbabio.2014.11.001

• Respiratory chain
• Oxidase biogenesis
• Cu-A center
• Copper chaperone
• Sco1

The biogenesis of the mitochondrial cytochrome c oxidase is a complex process involving the stepwise assembly of its multiple subunits encoded by two genetic systems. Moreover, several chaperones are required to recruit and insert the redox-active metal centers into subunits I and II, two a-type hemes and a total of three copper ions, two of which form the Cu-A center located in a hydrophilic domain of subunit II. The copper-binding Sco protein(s) have been implicated with the metallation of this site in various model organisms.
Here we analyze the role of the two Sco homologues termed ScoA and ScoB, along with two other copper chaperones, on the biogenesis of the cytochrome c oxidase in the bacterium Para coccus denitrificans by deleting each of the four genes individually or pairwise, followed by assessing the functionality of the assembled oxidase both in intact membranes and in the purified enzyme complex. Copper starvation leads to a drastic decrease of oxidase activity in membranes from strains involving the scoB deletion. This loss is shown to be of dual origin, (i) a severe drop in steady-state oxidase levels in membranes, and (ii) a diminished enzymatic activity of the remaining oxidase complex, traced back to a lower copper content, specifically in the Cu-A site of the enzyme. Neither of the other proteins addressed here, ScoA or the two PCu proteins, exhibit a direct effect on the metallation of the Cu-A site in P. denitrificans, but are discussed as potential interaction partners of ScoB.

• 出版日期2015-2