Characterization of the phenylurea hydrolases A and B: founding members of a novel amidohydrolase subgroup

Khurana, Jeevan; Jackson, Colin J.; Scott, Colin; Pandey, Gyanendra; Horne, Irene; Russell, Robyn J.; Herlt, Anthony J.; Easton, Christopher J.; Oakeshott, John G.

doi:10.1042/bj20081488

Cited by 59 publications

(81 citation statements)

References 44 publications

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“…The highest similarity (48 to 50% amino acid sequence identity) was observed with phenylurea hydrolases from A. globiformis D47 and Mycobacterium brisbanense JK1 (19).…”

Section: Resultsmentioning

confidence: 83%

“…High homology (Ͼ40% of amino acid identity) was observed only with the phenylurea hydrolases PuhA and PuhB. These enzymes, which are involved in the degradation of several phenylurea herbicides such as diuron and linuron (19), were found to oligomerize as homohexamers. Analysis of proteins of subfamily cd1292 identified after a PSI BLAST search to be related to molinate hydrolase identified a set of 853 proteins to be the most closely related.…”

Section: Discussionmentioning

confidence: 99%

“…ACL11849) or Mycobacterium brisbanense (PuhB; GenBank accession no. ACL11830) (19). On the basis of the N-terminal and inner sequences of the native protein, the gene encoding molinate hydrolase was localized as described in Materials and Methods.…”

Section: Resultsmentioning

confidence: 99%

“…The majority of the members described in the amidohydrolase superfamily are zinc dependent (divalent zinc ion or dinuclear zinc pair) (27). Also, PuhA and PuhB are described as containing a mononuclear zinc ion per subunit (19). Dinuclear Ni 2ϩ and mono Fe 2ϩ centers are present in some other metaldependent hydrolases (27).…”

Section: Discussionmentioning

confidence: 99%

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Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

et al. 2011

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A new pathway of molinate mineralization has recently been described. Among the five members of the mixed culture able to promote such a process, Gulosibacter molinativorax ON4 T has been observed to promote the initial breakdown of the herbicide into ethanethiol and azepane-1-carboxylate. In the current study, the gene encoding the enzyme responsible for molinate hydrolysis was identified and heterologously expressed, and the resultant active protein was purified and characterized. Nucleotide sequence analysis revealed that the gene encodes a 465-amino-acid protein of the metal-dependent hydrolase A subfamily of the amidohydrolase superfamily with a predicted molecular mass of 50.9 kDa. Molinate hydrolase shares the highest amino acid sequence identity (48 to 50%) with phenylurea hydrolases of Arthrobacter globiformis and Mycobacterium brisbanense. However, in contrast to previously described members of the metal-dependent hydrolase A subfamily, molinate hydrolase contains cobalt as the only active-site metal.Molinate is a herbicide which is extensively applied to rice fields worldwide. When this thiocarbamate herbicide is applied to the flooded paddies, it dissipates into the environment largely through volatilization. However, (photo)chemical and microbiological molinate transformation also occurs (28), resulting in accumulation of oxidized metabolites, such as oxomolinate and molinate sulfoxide (11, 13), which have increased toxicity (5). The only biological system described so far as being able to mineralize molinate and use the herbicide as the sole source of carbon, energy, and nitrogen is a five-membered bacterial mixed culture (2, 6). Among the five community members, Gulosibacter molinativorax ON4 T (gen. nov., sp. nov.), the only representative of this genus thus far (21), is responsible for the initial breakdown of molinate. In contrast to previously described molinate transformation reactions (13), G. molinativorax ON4T cleaves the thioester bond of molinate, releasing ethanethiol and azepane-1-carboxylate (ACA) (Fig. 1) (1). While this hydrolysis proceeds in the absence of oxygen, the further metabolism and mineralization of ACA by G. molinativorax ON4 T necessitate oxygen. Ethanethiol is not transformed by this organism but is spontaneously oxidized to diethyl disulfide. At molinate concentrations of Ͼ2 mM, the accumulating sulfur compounds are toxic for G. molinativorax ON4T and molinate mineralization is achieved only when other mixed-culture members able to degrade the sulfurcontaining metabolites are present (1, 2).In the present study, the molinate hydrolase (MolA) from G. molinativorax ON4T responsible for the key step of molinate breakdown was purified and characterized. The encoding gene was identified and expressed in Escherichia coli. This enzyme belongs to the metal-dependent hydrolase A subfamily of the amidohydrolase superfamily; however, in contrast to previously characterized members, it contains cobalt as a cofactor. To the best of our knowledge, this is the first description of an...

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“…The highest similarity (48 to 50% amino acid sequence identity) was observed with phenylurea hydrolases from A. globiformis D47 and Mycobacterium brisbanense JK1 (19).…”

Section: Resultsmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

et al. 2011

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“…In addition, phenylurea hydrolase-encoding genes puhA and puhB were identified in the linuron-degrading actinomycetes Arthrobacter globiformis D47 (52) and Mycobacterium brisbanense JK1 (23), respectively. PuhA and PuhB form a novel branch within the metal-dependent amidohydrolase superfamily (23). Regarding the degradation of DCA, Dejonghe (9) and Breugelmans et al (6) found indications for the involvement of a multicomponent aniline dioxygenase enzyme in DCA degradation in Variovorax sp.…”

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confidence: 99%

A Novel Hydrolase Identified by Genomic-Proteomic Analysis of Phenylurea Herbicide Mineralization by Variovorax sp. Strain SRS16

Bers

Leroy

Breugelmans

et al. 2011

Appl Environ Microbiol

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The soil bacterial isolate Variovorax sp. strain SRS16 mineralizes the phenylurea herbicide linuron. The proposed pathway initiates with hydrolysis of linuron to 3,4-dichloroaniline (DCA) and N,O-dimethylhydroxylamine, followed by conversion of DCA to Krebs cycle intermediates. Differential proteomic analysis showed a linuron-dependent upregulation of several enzymes that fit into this pathway, including an amidase (LibA), a multicomponent chloroaniline dioxygenase, and enzymes associated with a modified chlorocatechol ortho- The phenylurea herbicide linuron is a nonselective preemergent herbicide that acts as a photosystem II inhibitor. The herbicide is globally used to control a wide variety of annual and perennial broadleaf and grassy weeds in agricultural land. Microbial degradation is considered an important mechanism in the dissipation of linuron and other phenylurea herbicides in the environment. Several bacterial strains (39, 46), as well as consortia (5, 10), able to degrade and even use the compound as a sole source of carbon and nitrogen have been reported. Although derived from different geographical locations, most of the linuron-catabolizing isolates, either individual strains or key members of linurondegrading consortia, belong to the genus Variovorax. This suggests that this genus plays an important role in linuron degradation in soil. The proposed pathway of linuron catabolism starts with amide hydrolysis to 3,4-dichloroaniline (DCA) and N,O-dimethylhydroxylamine (N,O-DMHA) (Fig. 1). DCA is harmful and recalcitrant, while N,O-DMHA is not and degraded easily. Several linuron-degrading Variovorax strains, in addition to mediating linuron hydrolysis, are able to use DCA as the sole carbon source and mineralize it. To date, little is known about the genes and enzymes responsible for linuron and DCA degradation. Engelhardt et al. (13) described an arylacyl amidase responsible for conversion of linuron to DCA in Bacillus sphaericus ATCC 12123. In addition, phenylurea hydrolase-encoding genes puhA and puhB were identified in the linuron-degrading actinomycetes Arthrobacter globiformis D47 (52) and Mycobacterium brisbanense JK1 (23), respectively. PuhA and PuhB form a novel branch within the metal-dependent amidohydrolase superfamily (23). Regarding the degradation of DCA, Dejonghe (9) and Breugelmans et al. (6) found indications for the involvement of a multicomponent aniline dioxygenase enzyme in DCA degradation in Variovorax sp. strain WDL1. However, the genes responsible for DCA degradation in linuron-mineralizing bacteria have not yet been identified.We report here on the identification of the linuron and DCA degradation genes in the linuron-mineralizing strain Variovorax sp. strain SRS16 (46). The enzyme responsible for hydrolysis of linuron was purified and characterized. The expression of the catabolic genes under different conditions

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Diuron mineralisation in a Mediterranean vineyard soil: impact of moisture content and temperature

Sebaï¹,

Devers²,

Lagacherie³

et al. 2010

Pest. Manag. Sci.

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Characterization of the phenylurea hydrolases A and B: founding members of a novel amidohydrolase subgroup

Cited by 59 publications

References 44 publications

Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

A Novel Hydrolase Identified by Genomic-Proteomic Analysis of Phenylurea Herbicide Mineralization by Variovorax sp. Strain SRS16

Diuron mineralisation in a Mediterranean vineyard soil: impact of moisture content and temperature

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Characterization of the phenylurea hydrolases A and B: founding members of a novel amidohydrolase subgroup

Cited by 59 publications

References 44 publications

Gulosibacter molinativorax ON4 T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

Gulosibacter molinativorax ON4 T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

A Novel Hydrolase Identified by Genomic-Proteomic Analysis of Phenylurea Herbicide Mineralization by Variovorax sp. Strain SRS16

Diuron mineralisation in a Mediterranean vineyard soil: impact of moisture content and temperature

Contact Info

Product

Resources

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Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase