A manganese-dependent dioxygenase from Arthrobacter globiformis CM-2 belongs to the major extradiol dioxygenase family

Boldt, Yvonne R.; Sadowsky, Michael J.; Ellis, Lynda B. M.; Que, Lawrence; Wackett, Lawrence P.

doi:10.1128/jb.177.5.1225-1232.1995

Cited by 92 publications

(78 citation statements)

References 42 publications

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“…The quantity of homologous C 2 3 0 gene abundance detected in all of the environmental DNA samples fell in the linear range of detection. (Boldt et al 1995). Only the 2 P. putida strains gave positive hybridization signals (data not shown), indicating that the xylE probe was specific for more highly conserved C230 genes, many of which are known to be plasmid-encoded (Ghosal et al 1987, Bartilson & Shingler 1989, Assinder & Willialns 1990.…”

Section: Resultsmentioning

confidence: 99%

Quantification of catechol 2,3-dioxygenase gene homology and benzoate utilization in intertidal sediments

Francis¹,

Francis²,

Golet³

et al. 1998

Aquat. Microb. Ecol.

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The catechol 2,3-dioxygenase (C230) gene, xylE, from the TOL plasmid pathway was used to probe naturally occurring bacterial communities in an intertidal microbial mat. Bound probe was quantified by densitometric analysis of slot blots using colorimetric detection of hybridization between the probe and total DNA extracts from the sediments. The C230 gene encodes the key ringbrealung enzyme of the toluene degradation pathway, of which benzoate is an intermediate. Radiotracer experiments using I4C-benzoate detected benzoate mineralization in these sedirnents, corroborating the presence of both the genetic potential and in situ actlvity for this transformation.

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Section: Resultsmentioning

confidence: 99%

Quantification of catechol 2,3-dioxygenase gene homology and benzoate utilization in intertidal sediments

Francis¹,

Francis²,

Golet³

et al. 1998

Aquat. Microb. Ecol.

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“…Several of the Mn-containing analogues are also homologues (13,14). However, in general, redox-active Mn seems to function as an oxidant in enzymes, and Mn does not occur biologically at potentials as low as those of the low-potential Fe enzymes.…”

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confidence: 99%

Novel Insights into the Basis for Escherichia coli Superoxide Dismutase's Metal Ion Specificity from Mn-Substituted FeSOD and Its Very High E_m

2001

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Fe and Mn are both entrained to the same chemical reaction in apparently superimposable superoxide dismutase (SOD) proteins. However, neither Fe-substituted MnSOD nor Mn-substituted FeSOD is active. We have proposed that the two SOD proteins must apply very different redox tuning to their respective metal ions and that tuning appropriate for one metal ion results in a reduction potential (E m ) for the other metal ion that is either too low (Fe) or too high (Mn) [Vance and Miller (1998) J. Am. Chem. Soc. 120, 461-467]. We have demonstrated that this is true for Fe-substituted MnSOD from Escherichia coli and that this metal ion-protein combination retains the ability to reduce but not oxidize superoxide. We now demonstrate that the corollary is also true: Mn-substituted FeSOD [Mn(Fe)SOD] has a very high E m . Specifically, we have measured the E m of E. coli MnSOD to be 290 mV vs NHE. We have generated Mn(Fe)SOD and find that Mn is bound in an environment similar to that of the native (Mn)SOD protein. However, the E m is greater than 960 mV vs NHE and much higher than MnSOD's E m of 290 mV. We propose that the different tuning stems from different hydrogen bonding between the proteins and a molecule of solvent that is coordinated to the metal ion in both cases. Because a proton is taken up by SOD upon reduction, the protein can exert very strong control over the E m , by modulating the degree to which coordinated solvent is protonated, in both oxidation states. Thus, coordinated solvent molecules may have widespread significance as "adapters" by which proteins can control the reactivity of bound metal ions.

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“…In this study, we examine these aspects of extradiol dioxygenase catalysis by using two enzymes that both catalyze the oxygen-dependent extradiol cleavage of 3,4-dihydroxyphenylacetate (also known as homoprotocatechuate [HPCA]) to produce 5-carboxymethyl-2-hydroxymuconic semialdehyde. Interestingly, homoprotocatechuate 2,3-dioxygenase (2,3-HPCD) from Arthrobacter globiformis (MndD) utilizes Mn 2ϩ (7,86), whereas the enzyme isolated from Brevibacterium fuscum (Bf 2,3-HPCD) utilizes Fe 2ϩ (48,84). Primary sequence analysis indicates that MndD has 14 of the 18 amino acid residues previously identified as conserved in the type I family (7,32).…”

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confidence: 99%

“…Type I also includes most of the catechol 2,3-dioxygenases (2,3-CTDs), such as the xylE gene product from the TOL plasmid of P. putida mt-2 (51). A consensus sequence for the metal binding region of type I enzymes has been defined (7,22). The type II extradiol dioxygenases include such enzymes as protocatechuate 4,5-dioxygenase (LigAB) from Pseudomonas paucimobilis (53), which has two different types of subunits, and 2,3-CTD from Alcaligenes eutrophus JMP222 (38).…”

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Crystallographic Comparison of Manganese- and Iron-Dependent Homoprotocatechuate 2,3-Dioxygenases

et al. 2004

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The X-ray crystal structures of homoprotocatechuate 2,3-dioxygenases isolated from Arthrobacter globiformis and Brevibacterium fuscum have been determined to high resolution. These enzymes exhibit 83% sequence identity, yet their activities depend on different transition metals, Mn 2؉ and Fe 2؉ , respectively. The structures allow the origins of metal ion selectivity and aspects of the molecular mechanism to be examined in detail. The homotetrameric enzymes belong to the type I family of extradiol dioxygenases (vicinal oxygen chelate superfamily); each monomer has four ␤␣␤␤␤ modules forming two structurally homologous N-terminal and C-terminal barrel-shaped domains. The active-site metal is located in the C-terminal barrel and is ligated by two equatorial ligands, H214 NE1 and E267 OE1 ; one axial ligand, H155 NE1 ; and two to three water molecules. The first and second coordination spheres of these enzymes are virtually identical (root mean square difference over all atoms, 0.19 Å), suggesting that the metal selectivity must be due to changes at a significant distance from the metal and/or changes that occur during folding. The substrate (2,3-dihydroxyphenylacetate [HPCA]) chelates the metal asymmetrically at sites trans to the two imidazole ligands and interacts with a unique, mobile C-terminal loop. The loop closes over the bound substrate, presumably to seal the active site as the oxygen activation process commences. An "open" coordination site trans to E267 is the likely binding site for O 2 . The geometry of the enzyme-substrate complexes suggests that if a transiently formed metal-superoxide complex attacks the substrate without dissociation from the metal, it must do so at the C-3 position. Second-sphere active-site residues that are positioned to interact with the HPCA and/or bound O 2 during catalysis are identified and discussed in the context of current mechanistic hypotheses.Bacterial ring-cleaving dioxygenases are critical enzymes in the catabolism of aromatic compounds that enter the environment from a myriad of sources (9,17,18,44). The substrates for most of these enzymes are ortho-or para-dihydroxylated aromatics and molecular oxygen. Both atoms of oxygen from O 2 are incorporated into the product as the ring is cleaved. The resulting aliphatic products are further metabolized to intermediates of core metabolic cycles through well-established pathways (18,55,74).Dioxygenases that act on ortho-dihydroxylated aromatic compounds are divided into two classes, termed intradiol and extradiol, which differ in their mode of ring cleavage and the oxidation state of the active-site metal (44, 63). Intradiol dioxygenases utilize Fe 3ϩ and cleave the bond between the carbons bearing the two hydroxyls; extradiol dioxygenases utilize Fe 2ϩ or, rarely, Mn 2ϩ and cleave one of the carbon-carbon bonds adjacent to the ortho-hydroxyl substituents. Although intradiol and extradiol dioxygenases oxidize an overlapping set of substrates, they are not structurally related and are proposed to have fundamentally differ...

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A manganese-dependent dioxygenase from Arthrobacter globiformis CM-2 belongs to the major extradiol dioxygenase family

Cited by 92 publications

References 42 publications

Quantification of catechol 2,3-dioxygenase gene homology and benzoate utilization in intertidal sediments

Quantification of catechol 2,3-dioxygenase gene homology and benzoate utilization in intertidal sediments

Novel Insights into the Basis for Escherichia coli Superoxide Dismutase's Metal Ion Specificity from Mn-Substituted FeSOD and Its Very High E_m

Crystallographic Comparison of Manganese- and Iron-Dependent Homoprotocatechuate 2,3-Dioxygenases

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A manganese-dependent dioxygenase from Arthrobacter globiformis CM-2 belongs to the major extradiol dioxygenase family

Cited by 92 publications

References 42 publications

Quantification of catechol 2,3-dioxygenase gene homology and benzoate utilization in intertidal sediments

Quantification of catechol 2,3-dioxygenase gene homology and benzoate utilization in intertidal sediments

Novel Insights into the Basis for Escherichia coli Superoxide Dismutase's Metal Ion Specificity from Mn-Substituted FeSOD and Its Very High Em

Crystallographic Comparison of Manganese- and Iron-Dependent Homoprotocatechuate 2,3-Dioxygenases

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Novel Insights into the Basis for Escherichia coli Superoxide Dismutase's Metal Ion Specificity from Mn-Substituted FeSOD and Its Very High E_m