Cytochrome c550 is an essential component of the quinoprotein ethanol oxidation system in Pseudomonas aeruginosa: cloning and sequencing of the genes encoding cytochrome c550 and an adjacent acetaldehyde dehydrogenase.

Abstract

Pseudomonas aeruginosa ATCC 17933 grown aerobically on ethanol produces a soluble cytochrome c550 together with a quinoprotein ethanol dehydrogenase. A 3.2 kb genomic DNA fragment containing the gene encoding cytochrome c550 was cloned and sequenced. Two other complete and two truncated ORFs were also identified. A truncated ORF encoding the quinoprotein ethanol dehydrogenase (exaA) was found upstream of the cytochrome c550 gene (exaB) and in reverse orientation. An ORF encoding a NAD(+)-dependent acetaldehyde dehydrogenase (exaC) was located downstream of the cytochrome c550 gene and in the same orientation. Another ORF showed similarity to the pqqA gene and a truncated ORF similarity to the pqqB gene, both involved in the biosynthesis of the prosthetic group PQQ. The organization of these genes was found to be different from the well-studied methanol oxidation system in methylotrophic bacteria. The deduced amino acid sequence of cytochrome c550 from P. aeruginosa showed some similarity to cytochrome c6 of the alga Chlamydomonas reinhardtii and the haem domain of quinohaemoprotein alcohol dehydrogenases of acetic acid bacteria, but no similarity to the soluble cytochrome cL of the quinoprotein methanol oxidation system of methylotrophs could be detected. A mutant of P. aeruginosa with an interrupted cytochrome c550 gene was unable to grow on ethanol, which proves that cytochrome c550 is an essential component of the ethanol oxidation system in this organism.

• Authors: Max Schobert, Helmut Görisch
• Journal: Microbiology (Reading, England) (Microbiology (Reading)) Vol. 145 ( Pt 2) Pg. 471-481 (Feb 1999) ISSN: 1350-0872 [Print] England
• PMID: 10075429 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cytochrome c Group
• Quinones
• Recombinant Proteins
• Ethanol
• cytochrome C-550
• Aldehyde Oxidoreductases
• aldehyde dehydrogenase (NAD(P)+)

Topics

• Aldehyde Oxidoreductases (chemistry, genetics, metabolism)
• Amino Acid Sequence
• Cloning, Molecular
• Cytochrome c Group (chemistry, genetics, metabolism)
• Escherichia coli (genetics)
• Ethanol (metabolism)
• Genes, Bacterial
• Genetic Complementation Test
• Molecular Sequence Data
• Mutation
• Oxidation-Reduction
• Physical Chromosome Mapping
• Pseudomonas aeruginosa (chemistry, enzymology, genetics, growth & development)
• Quinones (metabolism)
• Recombinant Proteins (metabolism)
• Restriction Mapping
• Sequence Alignment
• Sequence Analysis, DNA