Nucleotide Sequence of the Gene Coding for Four Subunits of Cytochrome c Oxidase from the Thermophilic Bacterium PS31

Abstract

The gene coding for four subunits of cytochrome aa3-type oxidase was isolated from a genomic DNA library of the thermophilic bacterium PS3 and sequenced. The N-terminus of each subunit was also sequenced to verify the initiation site of the reading frame. The deduced amino acid sequences contained 615 amino acid residues for subunit I (CO1/caaB product), 333 residues for subunit II (CO2/caaA product), 207 residues for subunit III (CO3/caaC product), and 109 residues for subunit IV (CO4/caaD product) after processing. Re-examination of the sequencing of caa revealed a longer open reading frame for CO1, which contains 14 transmembrane segments instead of 12 [Sone et al. (1988) J. Biochem. 103, 606-610], although the main portions of the sequences constituting cytochrome a (FeA), cytochrome a3 (FeB), and CuB are correct. PS3 CO2 has an additional sequence for cytochrome c after the CuA binding protein portion with 2 transmembrane segments, which is homologous to the mitochondrial counterpart. PS3 CO3 has DCCD-binding glutamyl residues but contains only 5 transmembrane segments, unlike the mitochondrial counterpart, which has 7 segments. The subunits of PS3 cytochrome oxidase (aa3-type) show clear similarity in amino acid sequences with those of cytochrome bo-type oxidase from Escherichia coli as well, in spite of the difference of hemes. PS3 CO3 and CO4 are much more similar to E. coli CO3 and CO4 than to mitochondrial CO3 and CO4, respectively.

Cytochrome c oxidase contains an extra charged amino acid cluster in a new type of respiratory chain in the amino-acid-producing Gram-positive bacterium Corynebacterium glutamicum The GenBank/EMBL/DDBJ accession numbers for the sequences reported in this paper are AB052748 and AB052749.

“…The cleaved site, -M-A-G-C-, fits the signal-sequence motif of lipoproteins, -L\M-A\S-G-C-, and is similar to those of the subunits II of other oxidases (Ishizuka et al, 1990 ;Quirk et al, 1993 ;Ma et al, 1997 ;Bengtsson et al, 1999). It was empirically demonstrated that the thiol group is diacylglycerated in the caa $ -type cytochrome c oxidase from B. subtilis and the bo $ -type quinol oxidase from Escherichia coli.…”

Evidence ThatEscherichia coli ubiAProduct Is a Functional Homolog of Yeast COQ2, and the Regulation ofubiAGene Expression

“…32 ) PS3,26) and Saccharomyces cerevisiae,27) respectively. The deduced amino acid sequences of the ubiA product and COQ2 are from this study and Alexander Tzagoloff et al, 11) respectively.…”

Subunit III of cytochrome c oxidase is not involved in proton translocation: a site-directed mutagenesis study.

“…The homologous bacterial oxidases were originally thought to contain only two subunits (COI and COIl), but COII or its gene has been recently found in a number of species (for a review, see Saraste, 1990). COIl is thus likely to be a universal part of all aa3-type oxidases (Haltia et al, 1988;Buse et al, 1989;Ishizuka et al 1990; Saraste et al, 1991). Moreover, a homologous protein is present in the cytochrome o terminal oxidase complex of Escherichia coli .…”