Dioxo-, oxothio- and dithio-tungsten(VI) and tungsten(V) complexes of the ligand N,N′-Dimethyl-N,N′-bis(2-mercaptophenyl)ethylenediamine

Barnard, K.R.; Gable, Robert W.; Wedd, Anthony G.

doi:10.1007/s007750050177

Cited by 21 publications

(26 citation statements)

References 1 publication

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“…Rapid signals in other members of the XO family proteins have higher g av values than the slow signals, and in some cases may show hyperfine coupling with one or two protons [1]. They are assumed to be Michaelis complex analogs and believed to correspond to the sulfo form of the enzyme (Mo=S co‐ordination instead of the inactive reported desulfo form, Mo=O) [6,29–32]. D. alaskensis AOR rapid signal closely resembles the rapid signals observed in the XO family, and is apparently split by hyperfine interactions with proton(s).…”

Section: Resultsmentioning

confidence: 96%

Aldehyde oxidoreductase activity in Desulfovibrio alaskensis NCIMB 13491

Andrade

Brondino

Feio

et al. 2000

European Journal of Biochemistry

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A novel molybdenum iron-sulfur-containing aldehyde oxidoreductase (AOR) belonging to the xanthine oxidase family was isolated and characterized from the sulfate-reducing bacterium Desulfovibrio alaskensis NCIMB 13491, a strain isolated from a soured oil reservoir in Purdu Bay, Alaska. D. alaskensis AOR is closely related to other AORs isolated from the Desulfovibrio genus. The protein is a 97-kDa homodimer, with 0.6^0. . Three different EPR signals were recorded upon long reduction of the protein with excess dithionite: an almost axial signal split by hyperfine interaction with one proton associated with Mo(V) species and two rhombic signals with EPR parameters and relaxation behavior typical of [2Fe±2S] clusters termed Fe/S I and Fe/S II, respectively. EPR results reveal the existence of magnetic interactions between Mo(V) and one of the Fe/S clusters, as well as between the two Fe/S clusters. Redox titration monitored by EPR yielded midpoint redox potentials of 2275 and 2325 mV for the Fe/S I and Fe/S II, respectively. The redox potential gap between the two clusters is large enough to obtain differentiated populations of these paramagnetic centers. This fact, together with the observed interactions among paramagnetic centers, was used to assign the EPR-distinguishable Fe/S I and Fe/S II to those seen in the reported crystal structures of homologous enzymes.

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Section: Resultsmentioning

confidence: 96%

Aldehyde oxidoreductase activity in Desulfovibrio alaskensis NCIMB 13491

Andrade

Brondino

Feio

et al. 2000

European Journal of Biochemistry

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“…EPR signals associated with Mo(V) ions having g max > 2 have been reported in a few Mo-containing proteins [21]. These values are generally associated with Mo(V) ions sites coordinated by four sulfur atom donors from two pterin moieties and a Se-cysteine or a cysteine [22,23]. This value is unexpected for a protein of the XO family and is suggesting that the resting state for D. aminophilus AOR might be different to the resting state of other AORs.…”

Section: Molecular Biochemical and Kinetic Propertiesmentioning

confidence: 95%

Biochemical and spectroscopic characterization of an aldehyde oxidoreductase isolated from Desulfovibrio aminophilus

Thapper¹,

Rivas²,

Brondino³

et al. 2006

Journal of Inorganic Biochemistry

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“…The broadening of the W(V) ion signal at $70 K is unusual for an ion in a d 1 configuration and suggests that the W(V) ion is magnetically coupled to another faster relaxing paramagnet. EPR studies performed on model systems suggest a correlation between the g av value and the number of thiolate ligands in oxotungsten(V) species [25]. According to this correlation, the W center in D. alaskensis FDH (g av =1.934) should be bound to four thiolates.…”

Section: Growth Conditions and Enzymatic Propertiesmentioning

confidence: 97%

Incorporation of either molybdenum or tungsten into formate dehydrogenase from Desulfovibrio alaskensis NCIMB 13491; EPR assignment of the proximal iron-sulfur cluster to the pterin cofactor in formate dehydrogenases from sulfate-reducing bacteria

et al. 2003

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We report the characterization of the molecular properties and EPR studies of a new formate dehydrogenase (FDH) from the sulfate-reducing organism Desulfovibrio alaskensis NCIMB 13491. FDHs are enzymes that catalyze the two-electron oxidation of formate to carbon dioxide in several aerobic and anaerobic organisms. D. alaskensis FDH is a heterodimeric protein with a molecular weight of 126±2 kDa composed of two subunits, a=93±3 kDa and b=32±2 kDa, which contains 6±1 Fe/molecule, 0.4±0.1 Mo/molecule, 0.3±0.1 W/molecule, and 1.3±0.1 guanine monophosphate nucleotides. The UV-vis absorption spectrum of D. alaskensis FDH is typical of an iron-sulfur protein with a broad band around 400 nm. Variable-temperature EPR studies performed on reduced samples of D. alaskensis FDH showed the presence of signals associated with the different paramagnetic centers of D. alaskensis FDH. Three rhombic signals having g-values and relaxation behavior characteristic of [4Fe-4S] clusters were observed in the 5-40 K temperature range. Two EPR signals with all the g-values less than two, which accounted for less than 0.1 spin/protein, typical of mononuclear Mo(V) and W(V), respectively, were observed. The signal associated with the W(V) ion has a larger deviation from the free electron g-value, as expected for tungsten in a d 1 configuration, albeit with an unusual relaxation behavior. The EPR parameters of the Mo(V) signal are within the range of values typically found for the slow-type signal observed in several Mo-containing proteins belonging to the xanthine oxidase family of enzymes. Mo(V) resonances are split at temperatures below 50 K by magnetic coupling with one of the Fe/S clusters. The analysis of the inter-center magnetic interaction allowed us to assign the EPR-distinguishable iron-sulfur clusters with those seen in the crystal structure of a homologous enzyme.

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Dioxo-, oxothio- and dithio-tungsten(VI) and tungsten(V) complexes of the ligand N,N′-Dimethyl-N,N′-bis(2-mercaptophenyl)ethylenediamine

Cited by 21 publications

References 1 publication

Aldehyde oxidoreductase activity in Desulfovibrio alaskensis NCIMB 13491

Aldehyde oxidoreductase activity in Desulfovibrio alaskensis NCIMB 13491

Biochemical and spectroscopic characterization of an aldehyde oxidoreductase isolated from Desulfovibrio aminophilus

Incorporation of either molybdenum or tungsten into formate dehydrogenase from Desulfovibrio alaskensis NCIMB 13491; EPR assignment of the proximal iron-sulfur cluster to the pterin cofactor in formate dehydrogenases from sulfate-reducing bacteria

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