If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Locations of Mapped Genes:
|Superclasses:||Degradation/Utilization/Assimilation → Aromatic Compounds Degradation → Phenolic Compounds Degradation|
Phenylpropanoid compounds are abundant in natural environments where they can originate from putrefaction of proteins in soil or as breakdown products of plant materials such as lignin, various oils, and resins. Microbial catabolism of phenylpropanoids plays an important role in the natural degradation of these compounds (in [Diaz98]).
The degradation of the phenylpropanoids trans-cinnamate, 3-phenylpropionate (3-phenylpropanoate) and their hydroxylated derivatives has been reported in several members of the Proteobacteria and Actinobacteria [Dagley65, Andreoni86, Strickland73, Barnes97] including Escherichia coli K-12 and other strains of E. coli [Burlingame83a]. In E. coli K-12 this pathway is one of only two aromatic-ring-cleavage pathways that are found in the organism. The other aromatic-ring-cleavage pathway is phenylacetate degradation I (aerobic).
About This Pathway
The mhp and hca encoded enzymes of the pathway shown here can metabolize both trans-cinnamate and its hydroxylated derivatives, and 3-phenylpropionate and its hydroxylated derivatives (as shown in pathway 3-phenylpropanoate and 3-(3-hydroxyphenyl)propanoate degradation to 2-oxopent-4-enoate). In these pathways 2,3-dihydroxy-trans-cinnamate and 3-(2,3-dihydroxyphenyl)propionate undergo ring cleavage by the meta-cleaving dioxygenase MhpB [Diaz98].
This pathway ultimately yields fumarate and 2-oxopent-4-enoate, which is further degraded to pyruvate and acetyl-CoA as described in the linked pathway 2-oxopentenoate degradation. This pathway, including the portion that is described in 2-oxopentenoate degradation, has eight steps, making it one of the longest catabolic sequences known in E. coli [Burlingame86, Bugg93, Ferrandez97a].
E. coli K-12 can grow on 3-phenylpropionate, 3-(3-hydroxyphenyl)propionate, or 3-hydroxy-trans-cinnamate as sole source of carbon and energy. It cannot grow on trans-cinnamate for unknown reasons, although whole cells can readily oxidize this compound after growth with 3-phenylpropionate [Burlingame83a, Diaz98].
The fact that E. coli can degrade aromatic acids suggests a wider natural distribution for E. coli than the anaerobic environment of the animal gut [Burlingame83a]. As a facultative anaerobe, E. coli must be able to survive and grow in habitats such as soil, water and food, during interhost transfer.
Barnes97: Barnes MR, Duetz WA, Williams PA (1997). "A 3-(3-hydroxyphenyl)propionic acid catabolic pathway in Rhodococcus globerulus PWD1: cloning and characterization of the hpp operon." J Bacteriol 179(19);6145-53. PMID: 9324265
Burlingame86: Burlingame RP, Wyman L, Chapman PJ (1986). "Isolation and characterization of Escherichia coli mutants defective for phenylpropionate degradation." J Bacteriol 1986;168(1);55-64. PMID: 3531186
Diaz98: Diaz E, Ferrandez A, Garcia JL (1998). "Characterization of the hca cluster encoding the dioxygenolytic pathway for initial catabolism of 3-phenylpropionic acid in Escherichia coli K-12." J Bacteriol 1998;180(11);2915-23. PMID: 9603882
Ferrandez97a: Ferrandez A, Garcia JL, Diaz E (1997). "Genetic characterization and expression in heterologous hosts of the 3-(3-hydroxyphenyl)propionate catabolic pathway of Escherichia coli K-12." J Bacteriol 1997;179(8);2573-81. PMID: 9098055
Boxhammer08: Boxhammer S, Glaser S, Kuhl A, Wagner AK, Schmidt CL (2008). "Characterization of the recombinant Rieske [2Fe-2S] proteins HcaC and YeaW from E. coli." Biometals 21(4):459-67. PMID: 18286376
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Dunn05: Dunn G, Montgomery MG, Mohammed F, Coker A, Cooper JB, Robertson T, Garcia JL, Bugg TD, Wood SP (2005). "The structure of the C-C bond hydrolase MhpC provides insights into its catalytic mechanism." J Mol Biol 346(1);253-65. PMID: 15663942
Fleming00: Fleming SM, Robertson TA, Langley GJ, Bugg TD (2000). "Catalytic mechanism of a C-C hydrolase enzyme: evidence for a gem-diol intermediate, not an acyl enzyme." Biochemistry 39(6);1522-31. PMID: 10684634
He99: He Z, Spain JC (1999). "Comparison of the downstream pathways for degradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 (2-aminophenol pathway) and by Comamonas sp. JS765 (catechol pathway)." Arch Microbiol 171(5);309-16. PMID: 10382261
Henderson97: Henderson IM, Bugg TD (1997). "Pre-steady-state kinetic analysis of 2-hydroxy-6-keto-nona-2,4-diene-1,9-dioic acid 5,6-hydrolase: kinetic evidence for enol/keto tautomerization." Biochemistry 36(40);12252-8. PMID: 9315863
Lam97: Lam WW, Bugg TD (1997). "Purification, characterization, and stereochemical analysis of a C-C hydrolase: 2-hydroxy-6-keto-nona-2,4-diene-1,9-dioic acid 5,6-hydrolase." Biochemistry 36(40);12242-51. PMID: 9315862
Li05a: Li C, Montgomery MG, Mohammed F, Li JJ, Wood SP, Bugg TD (2005). "Catalytic mechanism of C-C hydrolase MhpC from Escherichia coli: kinetic analysis of His263 and Ser110 site-directed mutants." J Mol Biol 346(1);241-51. PMID: 15663941
Li06c: Li JJ, Li C, Blindauer CA, Bugg TD (2006). "Evidence for a gem-diol reaction intermediate in bacterial C-C hydrolase enzymes BphD and MhpC from 13C NMR spectroscopy." Biochemistry 45(41);12461-9. PMID: 17029401
Li06d: Li C, Li JJ, Montgomery MG, Wood SP, Bugg TD (2006). "Catalytic role for arginine 188 in the C-C hydrolase catalytic mechanism for Escherichia coli MhpC and Burkholderia xenovorans LB400 BphD." Biochemistry 45(41);12470-9. PMID: 17029402
Li08c: Li C, Hassler M, Bugg TD (2008). "Catalytic promiscuity in the alpha/beta-hydrolase superfamily: hydroxamic acid formation, C--C bond formation, ester and thioester hydrolysis in the C--C hydrolase family." Chembiochem 9(1);71-6. PMID: 18058773
Mendel04: Mendel S, Arndt A, Bugg TD (2004). "Acid-base catalysis in the extradiol catechol dioxygenase reaction mechanism: site-directed mutagenesis of His-115 and His-179 in Escherichia coli 2,3-dihydroxyphenylpropionate 1,2-dioxygenase (MhpB)." Biochemistry 43(42);13390-6. PMID: 15491145
Rajagopala14: Rajagopala SV, Sikorski P, Kumar A, Mosca R, Vlasblom J, Arnold R, Franca-Koh J, Pakala SB, Phanse S, Ceol A, Hauser R, Siszler G, Wuchty S, Emili A, Babu M, Aloy P, Pieper R, Uetz P (2014). "The binary protein-protein interaction landscape of Escherichia coli." Nat Biotechnol 32(3);285-90. PMID: 24561554
Schlosrich06: Schlosrich J, Eley KL, Crowley PJ, Bugg TD (2006). "Directed evolution of a non-heme-iron-dependent extradiol catechol dioxygenase: identification of mutants with intradiol oxidative cleavage activity." Chembiochem 7(12);1899-908. PMID: 17051653
Spence96: Spence EL, Kawamukai M, Sanvoisin J, Braven H, Bugg TD (1996). "Catechol dioxygenases from Escherichia coli (MhpB) and Alcaligenes eutrophus (MpcI): sequence analysis and biochemical properties of a third family of extradiol dioxygenases." J Bacteriol 1996;178(17);5249-56. PMID: 8752345
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