The binuclear iron centers of uteroferrin and the purple acid phosphatases

Doi, Kei; Antanaitis, B C; Aisen, Philip

doi:10.1007/3-540-50130-4_1

Cited by 103 publications

(68 citation statements)

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“…PAPs are glycosylated, resistant to inhibition by L-tartrate, and catalyze the hydrolysis of a broad range of phosphorylated substrates at acidic to neutral pH. 8,10,12,13 The enzyme isolated from mammals (pig, bovine, mouse, rat, and human [14][15][16][17][18][19][20] ) is a ∼35 kDa monomeric protein with an Fe(III)-Fe(II) center; the amino acid sequences of animal PAPs are highly conserved with at least 85% identity. 21 The characteristic color of PAPs is due to a charge-transfer transition (λ max ) 510-560 nm; ) ∼3000-4000 M -1 cm -1 ) in the active site from a conserved tyrosine ligand to the ferric ion.…”

Section: Biochemical Characterization and Functionmentioning

confidence: 99%

The Catalytic Mechanisms of Binuclear Metallohydrolases

et al. 2006

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Section: Biochemical Characterization and Functionmentioning

confidence: 99%

The Catalytic Mechanisms of Binuclear Metallohydrolases

et al. 2006

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Section: Introductionmentioning

confidence: 91%

“…The visible chromophore in the PAP enzyme has been associated with a tyrosinate to Fe III charge-transfer transition. 2,4 Resonance Raman studies on PAP´s, using visible excitation, confirm the presence of tyrosinate ring modes. 26 In a previous work, 27 a RR study of two isomeric dinuclear bis-μ-alkoxo complexes containing two Fe III centers, [Fe 2 (bbpnol) 2 ], revealed that the electronic coupling between the two centers is significantly increased in the cis-cis rather than in the cis-trans form.…”

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confidence: 91%

“…[1][2][3] In particular, the core Fe II Fe III is present in uteroferrin, a PAP from porcine uterus that is involved in the hydrolysis of orthophosphate monoesters and the regulation of the levels of phosphate at pH 4.9-6.0 . 1,4 The reduced form of the enzyme is pink (λ max =505-510 nm, ε ≈ 4000 L mol -1 cm -1 /Fe 2 ), and is active for hydrolysis, while the purple form, Fe III Fe III (λ max =550-570 nm, ε ≈ 4000 L mol -1 cm -1 / Fe 2 ) is inactive. 4 The similarity between the molar absorptivities of these two forms comes from the fact that the reduced iron is not part of the chromophoric group (tyrosinate-Fe III ).…”

Section: Introductionmentioning

confidence: 99%

“…1,4 The reduced form of the enzyme is pink (λ max =505-510 nm, ε ≈ 4000 L mol -1 cm -1 /Fe 2 ), and is active for hydrolysis, while the purple form, Fe III Fe III (λ max =550-570 nm, ε ≈ 4000 L mol -1 cm -1 / Fe 2 ) is inactive. 4 The similarity between the molar absorptivities of these two forms comes from the fact that the reduced iron is not part of the chromophoric group (tyrosinate-Fe III ). 3 Resonance Raman (RR) spectroscopy is a powerful tool in the investigation of molecular electronic excited states, since it allows the determination of the chromophoric group responsible for the electronic transition.…”

Section: Introductionmentioning

confidence: 99%

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Resonance Raman spectroscopy of FeII FeIII and FeIII FeIII model complexes containing an unsymmetrical dinucleating ligand: a biomimetic redox pair for uteroferrin

Gonçalves¹,

Horn²,

Lanznaster³

et al. 2006

J. Braz. Chem. Soc.

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(2), sendo bpbpmp a molécula 2-bis[{(2-piridilmetil)-aminometil}-6-{(2-hidroxibenzil)(2-piridilmetil)}-aminometil]-4-metilfenol. No complexo 1, o modo vibracional mais intensificado no espectro Raman é o correspondente ao ν(Fe-O phen_terminal ), observado em 608 cm -1 . Já no complexo 2, passa a ser o ν(CO phen_terminal ), observado em 1276 cm -1 . Estas diferenças são devidas às mudanças na estrutura eletrônica do esqueleto dinuclear unido por ponte fenolato, a qual é capaz de deslocalizar carga eletrônica entre os dois centros metálicos. bpbpmp is the proligand 2-bis[{(2-pyridylmethyl)-aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)}-aminomethyl]-4-methylphenol. For compound 1, the most enhanced vibrational mode in the Raman spectra is the ν(Fe-O phen_terminal ), observed at 608 cm -1 . For compound 2, the ν(CO phen_terminal ), which corresponds to the band at 1276 cm -1 , becomes the most enhanced one. These differences are ascribed to the changes in the electronic structure of the dinuclear phenolate bridged core upon oxidation. The phenolate bridge allows charge density transmission between the metal centers.Keywords: Resonance Raman spectroscopy, purple acid phosphatase, biomimetic analogue, mixed-valence, unsymmetrical ligand IntroductionPurple acid phosphatases (PAP´s) constitute a class of metalloenzymes that have been isolated from animals, plants and fungi. They contain a dinuclear core Fe III M II (M = Fe, Mn or Zn) in their active sites, which are able to catalyze the hydrolysis of a variety of phosphoric acid esters and anhydrides within the pH range 4-7. [1][2][3] In particular, the core Fe II Fe III is present in uteroferrin, a PAP from porcine uterus that is involved in the hydrolysis of orthophosphate monoesters and the regulation of the levels of phosphate at pH 4.9-6.0 . 1,4 The reduced form of the enzyme is pink (λ max =505-510 nm, ε ≈ 4000 L mol -1 cm -1 /Fe 2 ), and is active for hydrolysis, while the purple form, Fe III Fe III (λ max =550-570 nm, ε ≈ 4000 L mol -1 cm -1 / Fe 2 ) is inactive. 4 The similarity between the molar absorptivities of these two forms comes from the fact that the reduced iron is not part of the chromophoric group (tyrosinate-Fe III ). 3 Resonance Raman (RR) spectroscopy is a powerful tool in the investigation of molecular electronic excited states, since it allows the determination of the chromophoric group responsible for the electronic transition. In this way, electronic structure details can be accessed through this technique. It is worth to mention that it has been employed to investigate the nature of electronic transitions in a large range of systems, such as 1659 Gonçalves et al. Vol. 17, No. 8, 2006 inorganic coordination compounds, 5 metal-containing proteins 6-8 and their biomimetic analogues. 9-18 PAP's and related systems have also been studied by this technique, [19][20][21][22][23][24][25] aiming to characterize the chromophoric moiety for improved understanding of their electronic structure. The visible chromophore in the PAP enzyme has been as...

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Purple Acid Phosphatase

Vogel

Spener

Krebs

2004

Handbook of Metalloproteins

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Purple acid phosphatases (PAPs) hydrolyzing activated phosphoric acid esters and anhydrides have in common a two‐metal center with a tyrosine‐Fe(III) charge transfer transition responsible for the color. In the mammalian enzymes from the spleen, macrophages, osteoclasts, and uterine fluids, the second metal in the active site is Fe(II); whereas, the plant enzyme kidney bean PAP (kbPAP) has an Fe(III)–Zn(II) active center. The structure of the homodimeric 111‐kDa kbPAP shows the active site at the carboxy end of two sandwiched β–α–β–α–β motifs. The two metal ions are bridged monodentately by Asp164. The iron is further coordinated by Tyr167, His325, and Asp135, and the zinc by His286, His323, and Asn201. The active‐site structure is consistent with proposals on the mechanism of phosphate ester hydrolysis by nucleophilic attack on the phosphate by an Fe(III)‐coordinated hydroxide ion. Protein isolation, biological functions, sequences, activity, comparison of mammalian and plant PAPs, and the functional aspects of both types are discussed extensively.

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The binuclear iron centers of uteroferrin and the purple acid phosphatases

Cited by 103 publications

References 85 publications

The Catalytic Mechanisms of Binuclear Metallohydrolases

The Catalytic Mechanisms of Binuclear Metallohydrolases

Resonance Raman spectroscopy of FeII FeIII and FeIII FeIII model complexes containing an unsymmetrical dinucleating ligand: a biomimetic redox pair for uteroferrin

Purple Acid Phosphatase

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