A gene in Paracoccus for subunit III of cytochrome oxidase

Abstract

The region of Paracoccus denitrificans chromosome where the genes coding for cytochrome oxidase (cytochrome aa 3) subunits are located has been cloned. DNA sequencing revealed an open reading frame that codes for a protein homologous to the subunit III of the eukaryotic, mitochondrial enzyme. This subunit is absent from the isolated Paracoccus oxidase. It now seems that it is part of the native enzyme in the bacterial cytoplasmic membrane. This may explain the observed discrepancies in the function of the isolated enzyme.

Structure at 2.7 Å resolution of the Paracoccus denitrificans two-subunit cytochrome c oxidase complexed with an antibody F V fragment

“…The cytochrome c oxidase from P. denitrificans, however, was first isolated as a two-subunit enzyme using Triton X-100 as detergent (14). Later, the gene for subunit III was discovered (15) and a ''three-subunit enzyme'' was isolated subsequently with dodecyl-␤-D-maltoside as detergent (16). Recently, it was recognized that an additional small subunit, subunit IV, was present in such preparations (17,18).…”

Subunit II of cytochrome c oxidase from Paracoccus denitrificans

“…Apart from considerable further evidence for functional homologies to the mitochondrial enzyme [ll], clear-cut structural similarities have also been noted : immunological probing has been used to demonstrate a homology of subunit I1 of the Paracoccus oxidase to that of the mitochondrial (and other bacterial) enzymes [7], and amino acid sequences of short peptide fragments confirmed and extended this statement to both subunits [16]. Moreover, a gene of remarkable homology to subunit I11 of the mitochondrial oxidase has recently been isolated from Paracoccus and partially sequenced [17].Here we report the cloning and DNA sequence determination for the gene of subunit I1 of the Paracoccus oxidase as well as protein-chemical data on the polypeptide. This allows not only a comparison of the deduced amino acid sequence with known mitochondrial sequences, but is a prerequisite to future applications of in vitro mutagenesis techniques to probe structure/function relationships in an attempt to learn about molecular details of electron transport and proton translocation in cytochrome c oxidase.…”

“…Apart from considerable further evidence for functional homologies to the mitochondrial enzyme [ll], clear-cut structural similarities have also been noted : immunological probing has been used to demonstrate a homology of subunit I1 of the Paracoccus oxidase to that of the mitochondrial (and other bacterial) enzymes [7], and amino acid sequences of short peptide fragments confirmed and extended this statement to both subunits [16]. Moreover, a gene of remarkable homology to subunit I11 of the mitochondrial oxidase has recently been isolated from Paracoccus and partially sequenced [17].…”

“…Moreover, a gene of remarkable homology to subunit I11 of the mitochondrial oxidase has recently been isolated from Paracoccus and partially sequenced [17].…”

Homology between bacterial DNA and bovine mitochondrial DNA encoding cytochrome c oxidase subunit III

“…The very weak hybridization of the probe to P. denitrificans DNA under low stringency conditions is significant in view of the recent identification of a subunit III gene in P. denitrificans with approx. 30% nucleotide sequence homology to the subunit III probe [23]. This value is much less than the 5060% homology level needed to produce strong hybridization to the subunit III probe in our experiments.…”