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Yu L,
Blaser M,
Andrei PI,
Pierik AJ,
Selmer T,
( 2006 ) 4-Hydroxyphenylacetate decarboxylases: properties of a novel subclass of glycyl radical enzyme systems. PMID : 16878993 : DOI : 10.1021/bi060840b Abstract >>
The 4-hydroxyphenylacetate decarboxylases from Clostridium difficile and Clostridium scatologenes, which catalyze the formation of p-cresol, form a distinct group of glycyl radical enzymes (GREs). Cresol formation provides metabolic toxicity, which allows an active suppression of other microbes and may provide growth advantages for the producers in highly competitive environments. The GRE decarboxylases are characterized by a small subunit, which is not similar to any protein of known function in the databases, and provides unique properties that have not been observed in other GREs. Both decarboxylases are functional hetero-octamers (beta(4)gamma(4)), which contain iron-sulfur centers in addition to the glycyl radical prosthetic group. The small subunit is responsible for metal binding and is also involved in the regulation of the enzymes' oligomeric state and activity, which are triggered by reversible serine phosphorylation of the glycyl radical subunits. Biochemical data suggest that the iron-sulfur centers of the decarboxylases could be involved in the radical dissipation of previously activated enzymes in the absence of substrate. The cognate activating enzymes differ from their Pfl and Nrd counterparts in that up to two iron-sulfur centers, in addition to the characteristic SAM cluster, were found. Biochemical data suggested that these [4Fe-4S] centers are involved in the electron transfer to the SAM cluster but do not directly participate in the reductive cleavage of SAM. These data imply a tight regulation of p-cresol formation, which is necessary in order to avoid detrimental effects of the toxic product on the producers.
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2. |
Zhu Z,
Guo T,
Zheng H,
Song T,
Ouyang P,
Xie J,
( 2015 ) Complete genome sequence of a malodorant-producing acetogen, Clostridium scatologenes ATCC 25775(T). PMID : 26210291 : DOI : 10.1016/j.jbiotec.2015.07.013 Abstract >>
Clostridium scatologenes ATCC 25775(T) is an acetogenic anaerobic bacteria known to be capable of synthesizing volatile fatty acids and solvents from CO2 or CO on its autotrophic mode and producing 3-methylindole and 4-methylphenol on its heterotrophic mode. Here, we report the complete genome sequence of this strain, which might provide a lot of valuable information for developing metabolic engineering strategies to produce biofuels or chemicals from greenhouse gases.
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