Cloning of a gene encoding hydroxyquinol 1,2-dioxygenase that catalyzes both intradiol and extradiol ring cleavage of catechol.

Abstract

Two Escherichia coli transformants with catechol 1,2-dioxygenase activity were selected from a gene library of the benzamide-assimilating bacterium Arthrobacter species strain BA-5-17, which produces four catechol 1,2-dioxygenase isozymes. A DNA fragment isolated from one transformant contained a complete open reading frame (ORF). The deduced amino acid sequence of the ORF shared high identity with hydroxyquinol 1,2-dioxygenase. An enzyme expressed by the ORF was purified to homogeneity and characterized. When hydroxyquinol was used as a substrate, the purified enzyme showed 6.8-fold activity of that for catechol. On the basis of the sequence identity and substrate specificity of the enzyme, we concluded that the ORF encoded hydroxyquinol 1,2-dioxygenase. When catechol was used as a substrate, cis,cis-muconic acid and 2-hydroxymuconic 6-semialdehyde, which were products by the intradiol and extradiol ring cleavage activities, respectively, were produced. These results showed that the hydroxyquinol 1,2-dioxygenase reported here was a novel dioxygenase that catalyzed both the intradiol and extradiol cleavage of catechol.

• Authors: S Murakami, T Okuno, E Matsumura, S Takenaka, R Shinke, K Aoki
• Journal: Bioscience, biotechnology, and biochemistry (Biosci Biotechnol Biochem) Vol. 63 Issue 5 Pg. 859-65 (May 1999) ISSN: 0916-8451 [Print] England
• PMID: 10380628 (Publication Type: Journal Article)

Chemical References

• Catechols
• Oxygenases
• Dioxygenases
• hydroxyquinol 1,2-dioxygenase
• catechol

Topics

• Amino Acid Sequence
• Base Sequence
• Catalysis
• Catechols (metabolism)
• Cloning, Molecular
• Dioxygenases
• Hydrolysis
• Molecular Sequence Data
• Open Reading Frames
• Oxygenases (genetics, isolation & purification, metabolism)
• Phylogeny
• Sequence Homology, Amino Acid
• Substrate Specificity