Aromatic Ring Hydroxylating Dioxygenases

Parales, Rebecca E.; Resnick, Sol M.

doi:10.1007/0-387-28881-3_9

Cited by 60 publications

(61 citation statements)

References 293 publications

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“…Regarding mutants I324F and T365N, a similar outcome in the biotransformation of all substrates was found except for indene (9). A general reduction in enzyme activity for bromobenzene (5) and toluene (6) was observed for both mutants, with almost complete loss of activity for (6), and a slight decrease in yield for (5). Interestingly, changes in chemoselectivity were observed with both substrates (7) and (8).…”

Section: Biotransformation Resultsmentioning

confidence: 93%

“…[13c, e, 14-15] The TDO F366V mutant presented a drastic reduction in enzyme activity, larger than those observed for any other mutant. Indeed, the F366V variant was not capable of dihydroxylating the aromatic ring for substrates (6), (7) and (8), showing only 2% conversion for bromobenzene (5), the best substrate for the wild type biocatalyst. This general decrease in enzyme activity could be correlated, according to our model, with a general increment in the estimated binding DG, due to the decrease in substrate-receptor lipophilic interactions (see Table S4-S8).…”

Section: Biotransformation Resultsmentioning

confidence: 99%

“…[6] Although these enzymes have not been greatly used for synthetic purposes, they were deeply studied in the past for their potential application in bioremediation processes. In addition, NDO crystal structure has been early resolved, [10] Scheme 2.…”

Section: Mutant's Selection and Designmentioning

confidence: 99%

“…Salicylate Dioxygenases. [6] Toluene Dioxygenase (TDO) is the enzymatic complex that has been used to produce the vast majority of the cis-cyclohexadienediols used for synthetic applications. [1a, d] The biotransformation of arenes using this enzyme is carried out using whole cell biocatalysis with mutant organisms (P.putida F39/ D, P.putida UV4) or recombinant strains overexpressing the TDO genes.…”

Section: Introductionmentioning

confidence: 99%

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Site‐Directed Mutagenesis Studies on the Toluene Dioxygenase Enzymatic System: Role of Phenylalanine 366, Threonine 365 and Isoleucine 324 in the Chemo‐, Regio‐, and Stereoselectivity

et al. 2017

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Toluene Dioxygenase (TDO) enzymatic complex has been widely used as a biocatalyst for the regio-and enantioselective preparation of ciscyclohexadienediols, which are very important starting materials for organic synthesis. However, the lack of regio-and stereodiversity of the dioxygenation process by TDO and related dioxygenases constitutes a clear drawback when planning the use of these diols in synthetic schemes. In this work, we developed three TDO mutants in residues phenylalanine 366, threonine 365 and isoleucine 324, with the aim to alter the chemo-, regio-and stereoselectivity of the biotransformation of arenes. While no changes in the regioselectivity of the process were observed, dramatic variations in the chemo-and enantioselectivity were found for mutants I324F, T365N and F366 V in a substratedependent manner.

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Section: Biotransformation Resultsmentioning

confidence: 93%

Section: Biotransformation Resultsmentioning

confidence: 99%

Section: Mutant's Selection and Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Site‐Directed Mutagenesis Studies on the Toluene Dioxygenase Enzymatic System: Role of Phenylalanine 366, Threonine 365 and Isoleucine 324 in the Chemo‐, Regio‐, and Stereoselectivity

et al. 2017

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“…For example, in one study, Gan et al (2011) depicted the mineralization of 4-aminobenzensulfonate by Ralstonia and Hydrogenophaga sp. In this mineralization process, oxygen was introduced and degradation occurred through aromatic ring hydroxylation carried out by dioxygenase enzymes following a beta-ketoadipate pathway (Parales & Resnick, 2006). This process leads to the formation of non-toxic end products including carbon dioxide, ammonium and sulfates.…”

Section: Biodegradation Via Oxidative Processesmentioning

confidence: 99%

Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations

Ibekwe

Yang

et al. 2016

Science of The Total Environment

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Azo dyes and their intermediate degradation products are common contaminants of soil and groundwater in developing countries where textile and leather dye products are produced. The toxicity of azo dyes is primarily associated with their molecular structure, substitution groups and reactivity. To avoid contamination of natural resources and to minimize risk to human health, this wastewater requires treatment in an environmentally safe manner. This manuscript critically reviews biological treatment systems and the role of bacterial reductive and oxidative enzymes/processes in the bioremediation of dye-polluted wastewaters. Many studies have shown that a variety of culturable bacteria have efficient enzymatic systems that can carry out complete mineralization of dye chemicals and their metabolites (aromatic compounds) over a wide range of environmental conditions. Complete mineralization of azo dyes generally involves a two-step process requiring initial anaerobic treatment for decolorization, followed by an oxidative process that results in degradation of the toxic intermediates that are formed during the first step. Molecular studies have revealed that the first reductive process can be carried out by two classes of enzymes involving flavin-dependent and flavin-free azoreductases under anaerobic or low oxygen conditions. The second step that is carried out by oxidative enzymes that primarily involves broad specificity peroxidases, laccases and tyrosinases. This review focuses, in particular, on the characterization of these enzymes with respect to their enzyme kinetics and the environmental conditions that are necessary for bioreactor systems to treat azo dyes contained in wastewater.

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