Application of nitroarene dioxygenases in the design of novel strains that degrade chloronitrobenzenes.
Bottom Line: To address this need, we created engineered strains with a novel degradation pathway that reduces the total number of steps required to convert chloronitrobenzenes into compounds of central metabolism.We examined the ability of 2-nitrotoluene 2,3-dioxygenase from Acidovorax sp. strain JS42, nitrobenzene 1,2-dioxygenase (NBDO) from Comamonas sp. strain JS765, as well as active-site mutants of NBDO to generate chlorocatechols from chloronitrobenzenes, and identified the most efficient enzymes.Introduction of the wild-type NBDO and the F293Q variant into Ralstonia sp. strain JS705, a strain carrying the modified ortho pathway for chlorocatechol metabolism, resulted in bacterial strains that were able to sustainably grow on all three chloronitrobenzene isomers without addition of co-substrates or co-inducers.
Affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA 95616, USA.Show MeSH
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Mentions: We tested the activity of 2NTDO, NBDO and active‐site mutants of NBDO with 2CNB, 3CNB and 4CNB in Escherichia coli strains expressing the cloned dioxygenase genes. These substrates allowed us to characterize the behaviour of these dioxygenases towards molecules with two different electronegative functional groups. With each of these substrates, dioxygenation can occur at: (i) the nitro‐substituted carbon, (ii) the chloro‐substituted carbon or (iii) at positions distal to the nitro‐ or chloro‐substituted carbons. A variety of different substituted catechols or cis‐dihydrodiols could be produced depending on the regiospecificity of attack (Fig. 2).
Affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA 95616, USA.