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Characterization of the hca cluster encoding the dioxygenolytic pathway for initial catabolism of 3-phenylpropionic acid in Escherichia coli K-12.
- Source :
-
Journal of bacteriology [J Bacteriol] 1998 Jun; Vol. 180 (11), pp. 2915-23. - Publication Year :
- 1998
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Abstract
- We have identified, cloned, and sequenced the hca cluster encoding the dioxygenolytic pathway for initial catabolism of 3-phenylpropionic acid (PP) in Escherichia coli K-12. This cluster maps at min 57.5 of the chromosome and is composed of five catabolic genes arranged as a putative operon (hcaA1A2CBD) and two additional genes transcribed in the opposite direction that encode a potential permease (hcaT) and a regulator (hcaR). Sequence comparisons revealed that while hcaA1A2CD genes encode the four subunits of the 3-phenylpropionate dioxygenase, the hcaB gene codes for the corresponding cis-dihydrodiol dehydrogenase. This type of catabolic module is homologous to those encoding class IIB dioxygenases and becomes the first example of such a catabolic cluster in E. coli. The inducible expression of the hca genes requires the presence of the hcaR gene product, which acts as a transcriptional activator and shows significant sequence similarity to members of the LysR family of regulators. Interestingly, the HcaA1A2CD and HcaB enzymes are able to oxidize not only PP to 3-(2,3-dihydroxyphenyl)propionate (DHPP) but also cinnamic acid (CI) to its corresponding 2, 3-dihydroxy derivative. Further catabolism of DHPP requires the mhp-encoded meta fission pathway for the mineralization of 3-hydroxyphenylpropionate (3HPP) (A. Ferrández, J. L. García, and E. Díaz, J. Bacteriol. 179:2573-2581, 1997). Expression in Salmonella typhimurium of the mhp genes alone or in combination with the hca cluster allowed the growth of the recombinant bacteria in 3-hydroxycinnamic acid (3HCI) and CI, respectively. Thus, the convergent mhp- and hca-encoded pathways are also functional in S. typhimurium, and they are responsible for the catabolism of different phenylpropanoid compounds (3HPP, 3HCI, PP, and CI) widely available in nature.
- Subjects :
- Amino Acid Sequence
Base Sequence
Cloning, Molecular
Constitutive Androstane Receptor
Escherichia coli metabolism
Membrane Transport Proteins genetics
Models, Chemical
Molecular Sequence Data
Oxidoreductases genetics
Oxidoreductases metabolism
Oxygenases metabolism
Receptors, Cytoplasmic and Nuclear genetics
Restriction Mapping
Sequence Analysis, DNA
Trans-Activators genetics
Escherichia coli genetics
Escherichia coli Proteins
Genes, Bacterial genetics
Multigene Family genetics
Organic Anion Transporters
Oxygenases genetics
Phenylpropionates metabolism
Transcription Factors
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9193
- Volume :
- 180
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 9603882
- Full Text :
- https://doi.org/10.1128/JB.180.11.2915-2923.1998