Enantiomeric and mesomeric mandelate complexes of molybdenum – on their stereospecific formations and absolute configurations

Zhou, Zhao‐Hui; Zhao, Hong; Tsai, Khi-Rui

doi:10.1016/j.jinorgbio.2004.08.003

Cited by 19 publications

(13 citation statements)

References 44 publications

(41 reference statements)

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“…The two W-O(carboxylate) bonds (2.18-2.24 Å ) are much longer than the W-O distances involving terminal oxygen atoms (1.69-1.74 Å ). This is in good agreement with the distance observed between the carboxyl oxygen of (R)-homocitrate and molybdenum in the FeMo cofactor of A. vinelandii nitrogenase MoFe protein and with W/Mo-O(carboxyl) bond lengths determined in the crystal structures of mandelato, glycolato, and (S)-lactato molybdates and tungstates [28][29][30]. The short distances between the metal and the three terminal oxygen atoms are indicative of a partial double bond character.…”

Section: Resultssupporting

confidence: 87%

“…The short distances between the metal and the three terminal oxygen atoms are indicative of a partial double bond character. As discussed by Zhou et al [30], the stronger repulsion between such oxygen atoms results in increased bond angles between them and, in turn, compressed angles for bonds involving other atoms ( Table 2 The alignment was performed using DALI-lite [38] followed by minor manual adjustments. Secondary structure motifs are indicated above the sequences, and conserved residues involved in binding of substrate are highlighted in light blue for ModA/WtpA proteins discussed in this study (octahedral coordination) and in light green for ModA proteins with tetrahedral coordination involving the three terminal as well as the two carboxyl oxygens match well in the two noncrystallographically related AfModA monomers, the length of the W-O 4 bond does not and appears to be more flexible (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

et al. 2009

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Bacteria and archaea import molybdenum and tungsten from the environment in the form of the oxyanions molybdate (MoO 4 2-) and tungstate (WO 4 2-). These substrates are captured by an external, high-affinity binding protein, and delivered to ATP binding cassette transporters, which move them across the cell membrane.We have recently reported a crystal structure of the molybdate/tungstate binding protein ModA/WtpA from Archaeoglobus fulgidus, which revealed an octahedrally coordinated central metal atom. By contrast, the previously determined structures of three bacterial homologs showed tetracoordinate molybdenum and tungsten atoms in their binding pockets. Until then, coordination numbers above four had only been found for molybdenum/tungsten in metalloenzymes where these metal atoms are part of the catalytic cofactors and coordinated by mostly non-oxygen ligands. We now report a high-resolution structure of A. fulgidus ModA/WtpA, as well as crystal structures of four additional homologs, all bound to tungstate. These crystal structures match X-ray absorption spectroscopy measurements from soluble, tungstate-bound protein, and reveal the details of the distorted octahedral coordination. Our results demonstrate that the distorted octahedral geometry is not an exclusive feature of the A. fulgidus protein, and suggest distinct binding modes of the binding proteins from archaea and bacteria.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

et al. 2009

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“…This type of coordination is employed by all R-hydroxycarboxylates L in the [Mo VI O 2 L 2 ] 2-series. [8][9][10][11][12][13][14] The rather unusual feature of 6 is only partial deprotonation of the more acidic carboxylic group. The literature reports on a complex of an almost the same composition, [MoO 2 (glyc) 2 ] 2-, where both glycolates are fully deprotonated.…”

Section: Complexation Of Mo(v) With Glycolic Acidmentioning

confidence: 99%

Complexation of Molybdenum(V) with Glycolic Acid: An Unusual Orientation of Glycolato Ligand in {Mo₂O₄}²⁺ Complexes

2008

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(PyH)5[Mo(V)OCl4(H2O)]3Cl2 and (PyH)n[Mo(V)OBr4]n reacted with glycolic acid (H2glyc) or its half-neutralized ion (Hglyc(-)) to afford a series of novel glycolato complexes based on the {Mo(V)2O4}2+ structural core: (PyH)3[Mo2O4Cl4(Hglyc)]. (1)/ 2CH 3CN (1), (PyH) 3[Mo 2O 4Br 4(Hglyc)].Pr(i)OH(2), (PyH)2[Mo2O4(glyc) 2Py 2] (3), (PyH) 4[Mo 4O 8Cl 4(glyc) 2].2EtOH (4), and [Mo 4O 8(glyc) 2Py 4] (5) (Py = pyridine, C 5H 5N; PyH(+) = pyridinium cation, C 5H 5NH (+) and glyc (2-) = a doubly ionized glycolate, (-)OCH 2COO (-)). The compounds were fully characterized by X-ray crystallography and infrared spectroscopy. The Hglyc (-) ion binds to the {Mo 2O 4} (2+) core through a carboxylate end in a bidentate bridging manner, whereas the glyc (2-) ion adopts a chelating bidentate coordination through a deprotonated hydroxyl group and a monodentate carboxylate. The orientations of glyc (2-) ions in 3- 5 are such that the alkoxyl oxygen atoms occupy the sites opposite the multiply bonded oxides. {(C6H5) 4P}[Mo(VI)O 2(glyc)(Hglyc)] ( 6), an oxidized complex, features a reversed orientation of the glyc(2-) ion. The theoretical DFT calculations on the [Mo(V)2O4(glyc) 2Py 2](2-) and [Mo(VI)O2(glyc)2](2-) ions confirm that binding of glycolate with the alkoxyl oxygen to the site opposite the MoO bond is energetically more favorable in {Mo(V)2O4}(2+) species, whereas a reversed orientation of the ligand is preferred in Mo(VI) complexes. An explanation based on the orbital analysis is put forward.

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“…Interestingly this structure features octahedral W coordination; this differs from a number of molybdate binding proteins which contain Mo in a tetrahedral geometry with Mo-O distances of 1.76 [12]. In crystal structures of octahedral W complexes, such as that of bis(ammonium) D-bis((R)-mandelato-O,O')-dioxotungsten(VI) dihydrate [13], typically 3 different (1.7, 2.0, and 2.2 Å) W-O distances are found. Figure 3 shows the EXAFS of A. fulgidus ModA with tungstate till approx.…”

Section: Oxyanions In Biological Systemsmentioning

confidence: 86%

Anion binding in biological systems

Feiters

Meyer‐Klaucke

Kostenko

et al. 2009

J. Phys.: Conf. Ser.

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Enantiomeric and mesomeric mandelate complexes of molybdenum – on their stereospecific formations and absolute configurations

Cited by 19 publications

References 44 publications

Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

Complexation of Molybdenum(V) with Glycolic Acid: An Unusual Orientation of Glycolato Ligand in {Mo₂O₄}²⁺ Complexes

Anion binding in biological systems

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Enantiomeric and mesomeric mandelate complexes of molybdenum – on their stereospecific formations and absolute configurations

Cited by 19 publications

References 44 publications

Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

Complexation of Molybdenum(V) with Glycolic Acid: An Unusual Orientation of Glycolato Ligand in {Mo2O4}2+ Complexes

Anion binding in biological systems

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Complexation of Molybdenum(V) with Glycolic Acid: An Unusual Orientation of Glycolato Ligand in {Mo₂O₄}²⁺ Complexes