Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Comamonas testosteroni TA441 degrades 3-(3-hydroxyphenyl)propionate (3HPP) via the meta pathway. A gene cluster required for degradation of 3HPP was cloned from strain TA441 and sequenced. The genes encoding six catabolic enzymes, a flavin-type hydroxylase (mhpA), extradiol dioxygenase (mhpB), 2-keto-4-pentenoate hydratase (mhpD), acetaldehyde dehydrogenase (acylating) (mhpF), 4-hydroxy-2-ketovalerate aldolase (mhpE) and the meta cleavage compound hydrolase (mhpC), were found in this cluster, encoded in this order. mhpD and mhpF were separated by two genes, orf4 and orf5, which were not necessary for growth on 3HPP. The gene mhpR, encoding a putative transcriptional activator of the IcIR family, was located adjacent to mhpA in the opposite orientation. Disruption of the mhpB or mhpR genes affected growth on 3HPP or trans-3-hydroxycinnamate. The mhpB and mhpC gene products showed high specificity for 3-(2,3-dihydroxyphenyl)propionate (DHPP) and the meta cleavage compound produced from DHPP, respectively.
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PMID:Genetic organization and characteristics of the 3-(3-hydroxyphenyl)propionic acid degradation pathway of Comamonas testosteroni TA441. 1053 3

The expression of the mhp genes involved in the degradation of the aromatic compound 3-(3-hydroxyphenyl)propionic acid (3HPP) in Escherichia coli is dependent on the MhpR transcriptional activator at the Pa promoter. This catabolic promoter is also subject to catabolic repression in the presence of glucose mediated by the cAMP-CRP complex. The Pr promoter drives the MhpR-independent expression of the regulatory gene. In vivo and in vitro experiments have shown that transcription from the Pr promoter is downregulated by the addition of glucose and this catabolic repression is also mediated by the cAMP-CRP complex. The activation role of the cAMP-CRP regulatory system was further investigated by DNase I footprinting assays, which showed that the cAMP-CRP complex binds to the Pr promoter sequence, protecting a region centred at position -40.5, which allowed the classification of Pr as a class II CRP-dependent promoter. Open complex formation at the Pr promoter is observed only when RNA polymerase and cAMP-CRP are present. Finally, by in vitro transcription assays we have demonstrated the absolute requirement of the cAMP-CRP complex for the activation of the Pr promoter.
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PMID:Escherichia coli mhpR gene expression is regulated by catabolite repression mediated by the cAMP-CRP complex. 2096 94