Molybdenum active centre of DMSO reductase from Rhodobacter capsulatus: crystal structure of the oxidised enzyme at 1.82-Å resolution and the dithionite-reduced enzyme at 2.8-Å resolution

McAlpine, A. S.; McEwan, Alastair G.; Shaw, Anthony; Bailey, Susan

doi:10.1007/s007750050185

Cited by 147 publications

(178 citation statements)

References 1 publication

Supporting

Mentioning

162

Contrasting

Order By: Relevance

“…The first crystal structure for a protein of this family was the one reported for DMSOR from Rhodobacter sphaeroides (6). Members of the DMSOR family share the Mo-containing ␣-subunit, such as DMSOR (6)(7)(8), formate dehydrogenase (FDH)-H (9), and dissimilatory nitrate reductase (NIR) (10), but may also have one or two additional small subunits as observed in arsenite oxidase (11) and in tungsten-containing FDH-T (12) (␣-and ␤-subunits), and in NIR A (NARGHI) (13) and FDH-N (14) (␣-, ␤-, and ␥-subunits). The only protein ligand to the Mo ion is either a Ser (DMSOR, TH), Cys (dissimilatory NIR), Asp (NIR A), or seleno-Cys (FDHs).…”

mentioning

confidence: 99%

Crystal structure of pyrogallol–phloroglucinol transhydroxylase, an Mo enzyme capable of intermolecular hydroxyl transfer between phenols

Messerschmidt

Niessen

Abt

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The Mo enzyme transhydroxylase from the anaerobic microorganism Pelobacter acidigallici catalyzes the conversion of pyrogallol to phloroglucinol. Such trihydroxybenzenes and their derivatives represent important building blocks of plant polymers. None of the transferred hydroxyl groups originates from water during transhydroxylation; instead a cosubstrate, such as 1,2,3,5-tetrahydroxybenzene, is used in a reaction without apparent electron transfer. Here, we report on the crystal structure of the enzyme in the reduced Mo(IV) state, which we solved by single anomalousdiffraction technique. It represents the largest structure (1,149 amino acid residues per molecule, 12 independent molecules per unit cell), which has been solved so far by single anomalousdiffraction technique. Tranhydroxylase is a heterodimer, with the active Mo-molybdopterin guanine dinucleotide (MGD)2 site in the ␣-subunit, and three [4FeO4S] centers in the ␤-subunit. The latter subunit carries a seven-stranded, mainly antiparallel ␤-barrel domain. We propose a scheme for the transhydroxylation reaction based on 3D structures of complexes of the enzyme with various polyphenols serving either as substrate or inhibitor.

show abstract

mentioning

confidence: 99%

Crystal structure of pyrogallol–phloroglucinol transhydroxylase, an Mo enzyme capable of intermolecular hydroxyl transfer between phenols

Messerschmidt

Niessen

Abt

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…1a) (1)(2)(3). Although the recent proliferation of x-ray crystal structures for mononuclear molybdenum enzymes has revealed a common structure for the molybdopterin cofactor, they have also revealed considerable diversity in the molybdenum coordination environment (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). However, on the basis of the available crystallographic, spectroscopic, primary sequence, and cyanide inhibition data, these enzymes can be divided into three large families (Fig.…”

mentioning

confidence: 99%

“…In one of the two R. capsulatus Me 2 SO reductase x-ray structures, the oxidized form comprises a di-oxo-Mo(VI) center with one of the molybdopterin dithiolates fully dissociated (4). In the other set of R. capsulatus Me 2 SO reductase x-ray structures, the active site is refined as being 7-coordinate in both the oxidized and dimethyl sulfide (ME 2 S)-reduced forms, with both molybdopterin dithiolates attached, in addition to serinate and a spectator oxo group (5,6). There is also an exchangeable terminal oxygen ligand (oxo or hydroxo) that is lengthened (1.8 Å in the x-ray structure (5) and 1.9 Å by EXAFS (20)) compared with a typical terminal MoϭO group (1.7 Å) due to hydrogen bonding to a tryptophan residue, and it is this oxo group that constitutes the site of attack by Me 2 S (5,6,20).…”

mentioning

confidence: 99%

“…In the other set of R. capsulatus Me 2 SO reductase x-ray structures, the active site is refined as being 7-coordinate in both the oxidized and dimethyl sulfide (ME 2 S)-reduced forms, with both molybdopterin dithiolates attached, in addition to serinate and a spectator oxo group (5,6). There is also an exchangeable terminal oxygen ligand (oxo or hydroxo) that is lengthened (1.8 Å in the x-ray structure (5) and 1.9 Å by EXAFS (20)) compared with a typical terminal MoϭO group (1.7 Å) due to hydrogen bonding to a tryptophan residue, and it is this oxo group that constitutes the site of attack by Me 2 S (5,6,20). However, a catalytic scheme involving a spectator oxo group and a long terminal oxo group that is poised for oxygen atom transfer is not consistent with the resonance Raman and EXAFS data for R. sphaeroides Me 2 SO reductase (16,19).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Resonance Raman Characterization of Biotin Sulfoxide Reductase

Garton

Temple

Dhawan

et al. 2000

Journal of Biological Chemistry

View full text Add to dashboard Cite

Resonance Raman spectroscopy has been used to define active site structures for oxidized Mo(VI) and reduced Mo(IV) forms of recombinant Rhodobacter sphaeroides biotin sulfoxide reductase expressed in Escherichia coli. On the basis of 18 With the exception of nitrogenase, molybdenum enzymes catalyze formal oxygen atom transfer between water and substrate and contain an active site in which the molybdenum is coordinated by the dithiolene side chain of one or two molybdopterins (Fig. 1a) (1-3). Although the recent proliferation of x-ray crystal structures for mononuclear molybdenum enzymes has revealed a common structure for the molybdopterin cofactor, they have also revealed considerable diversity in the molybdenum coordination environment (2-11). However, on the basis of the available crystallographic, spectroscopic, primary sequence, and cyanide inhibition data, these enzymes can be divided into three large families (Fig. 1b) (1). Hydroxylases, such as Desulfovibrio gigas aldehyde oxidoreductase, xanthine oxidase, and xanthine dehydrogenase, represent the xanthine oxidase family, characterized by a Mo(VI) active site with a single molybdopterin, as well as terminal oxo and sulfido groups. The oxotransferase class of molybdoenzymes catalyzes direct oxygen atom transfer between substrate and water and can be divided into two families. The sulfite oxidase family, as represented by sulfite oxidase and assimilatory nitrate reductase, contains Mo(VI) ligated by two oxo groups in addition to a single molybdopterin and a cysteine residue. The dimethyl sulfoxide (Me 2 SO) reductase family comprises mono-oxoMo(VI) sites ligated by two molybdopterins and a protein side chain ligand such as serine, cysteine, or selenocysteine. In addition to Me 2 SO reductase, this family also includes formate dehydrogenase, dissimilatory nitrate reductase, and biotin sulfoxide (BSO) 1 reductase. BSO reductase is found in bacterial systems, such as Rhodobacter sphaeroides and Escherichia coli, and catalyzes the reduction of d-biotin d-sulfoxide to d-biotin (Fig. 2). Although the precise role for BSO reductase in bacterial metabolism has yet to be defined, potential physiological functions include scavenging biotin sulfoxide from the environment, reducing bound intracellular biotin that has become oxidized in an aerobic environment, and protecting the cell from oxidative damage (12). Extensive characterization of this enzyme has been limited due to the low natural abundance of the protein and its constitutive expression (13). However, R. sphaeroides BSO reductase has recently been heterologously expressed in E. coli and characterized as containing the molybdopterin guanine dinucleotide form of the molybdopterin cofactor (14). Using either reduced methyl viologen or NADPH as electron donor, the enzyme was found to exhibit broad substrate specificity and was able to catalyze reduction of nicotinamide-N-oxide, methionine sulfoxide, trimethylamine-N-oxide, and dimethyl sulfoxide with varying efficiencies, in addition to the reduction of biotin ...

show abstract

“…However, under an atmosphere of 13 CO, rapid exchange occurs into the -allyl complex, indicating that CO exchange, presumably by a tricarbonyl species, is viable. Next, coordination of malonate occurs to afford a seven-coordinate species 15, which should be an accessible intermediate because ample precedence exists for seven-coordinate Mo species (55)(56)(57). We depict this coordination occurring monodentate by an oxygen of the malonate rather than by the central carbon because of less steric crowding in the former.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic studies of the molybdenum-catalyzed asymmetric alkylation reaction

Hughes

Lloyd‐Jones

Krska

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

M etal-catalyzed asymmetric allylic alkylations are widely used in organic synthesis as efficient and practical methods to form carbon-carbon bonds with high enantio-and regioselectivity. Early work in this area focused on Pd complexes as catalysts, but their utility in organic synthesis was limited because, in general, unsymmetrical substrates afforded the achiral linear product (1-5). More recently, a limited number of ligands have been designed such that the branched product is now accessible with high enantiomeric excess (ee) by using Pd catalysis (6-9). Additionally, several other transition metals and ligands have been developed to regioselectively provide the branched product. These reactions can be grouped into two categories: (i) those that retain the stereochemistry of the branched substrate, and (ii) those in which the stereochemistry is lost. When starting with branched substrates, Ru (10-13), Rh (14,15), Fe (20,21), and W (22) complexes generally provide product wherein the stereochemistry of the substrate is retained, although recent exceptions have now been reported (23,24). These reactions may proceed by means of intermediates in which isomerization (K eq in Scheme 1) is slow relative to nucleophilic reaction. In contrast, Mo-based catalysis (25-39) proceeds with loss of substrate stereochemistry and provides the opportunity in reactions with asymmetric ligands to obtain high product ee, starting with either the linear substrate or racemic branched product (Scheme 1). These reactions proceed by a dynamic kinetic asymmetric transformation (40) with rapid equilibration of the two diastereomeric -allyl complexes before nucleophilic attack (Scheme 1).The stereochemistry of the two steps shown in Scheme 1 is arbitrarily shown as retention for oxidative addition and retention for the nucleophilic displacement. Extensive work on the Pd-catalyzed allylic alkylation has shown that the overall stereochemical outcome is generally retention, with the two steps of the process both proceeding with inversion (41-46). More recently, the Ir-catalyzed alkylation has also been shown to proceed by inversion-inversion in constrained systems (19). For the Mo-catalyzed reaction, Trost and coworkers (47, 48) have determined that the reaction proceeds with overall retention, but the stereochemistry of each step in the reaction has not been elucidated.A few studies have been carried out to determine the stereochemistry of the oxidative addition reaction in the Mocatalyzed reaction. Faller and Linebarrier (49), Rubio and Liebeskind (50), and Kuhl et al. (51) have shown that oxidative addition in stoichiometric reactions of Mo(CO) 3 (MeCN) 3 with cyclic and acyclic allylic acetates proceeds with retention of configuration. On the other hand, Ward et al. (52) discovered the stereochemistry of the oxidative addition is influenced by steric factors and experimental conditions, and oxidative addition of a single substrate can follow either an inversion or retention pathway, depending on the solvent and concentration, suggesti...

show abstract

Molybdenum active centre of DMSO reductase from Rhodobacter capsulatus: crystal structure of the oxidised enzyme at 1.82-Å resolution and the dithionite-reduced enzyme at 2.8-Å resolution

Cited by 147 publications

References 1 publication

Crystal structure of pyrogallol–phloroglucinol transhydroxylase, an Mo enzyme capable of intermolecular hydroxyl transfer between phenols

Crystal structure of pyrogallol–phloroglucinol transhydroxylase, an Mo enzyme capable of intermolecular hydroxyl transfer between phenols

Resonance Raman Characterization of Biotin Sulfoxide Reductase

Mechanistic studies of the molybdenum-catalyzed asymmetric alkylation reaction

Contact Info

Product

Resources

About