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Subunit change in cytochrome c oxidase: identification of the oxygen switch in Dictyostelium
Author(s) -
Bisson Roberto,
Vettore Silvia,
Aratri Elisabetta,
Sandonà Dorianna
Publication year - 1997
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/16.4.739
Subject(s) - biology , cytochrome c oxidase , dictyostelium , protein subunit , electron transport complex iv , oxygen , oxidase test , biochemistry , microbiology and biotechnology , enzyme , gene , chemistry , organic chemistry
Cytochrome c oxidase (COX) has a complex modular structure in eukaryotes. Depending on growth conditions, interchangeable isoforms of selected subunits are synthesized and combined to the evolutionarily conserved catalytic core of the enzyme. In Dictyostelium this structural make‐up is regulated by oxygen and involves two forms of the smallest subunit, termed VIIe and VIIs. Here we show that, in spite of a considerable sequence divergency, they are encoded by adjacent genes, linked ‘tail to head’ by only 800 bp. Deletion analyses reveal the presence of a short intergenic segment acting as an oxygen transcriptional switch. This structural organization and the different stability of the two subunit isoforms offer a molecular explanation for the extraordinary sensitivity to oxygen of the switching mechanism.