Binuclear Non-Heme Iron Enzymes

Mitić, Nataša; Schenk, Gerhard; Hanson, Graeme R.

doi:10.1007/978-0-387-84856-3_7

Cited by 4 publications

(4 citation statements)

References 620 publications

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“…The formation of a binuclear diiron(III) phosphate complex upon the addition of phosphate to the complex in methanol is supported by MS and is particularly pertinent in light of the fact that uteroferrin is also more readily oxidized upon phosphate binding. ,,− Relatively few EPR investigations of binuclear Fe III systems have been reported. ,,− Typically, the ions are coupled by μ-oxo bridges, mediating very strong antiferromagnetic exchange coupling resulting in a diamagnetic ( S tot = 0) ground state, predominant even at high temperatures. , Several complexes with EPR spectra similar to that observed here have been reported, but they typically only show population of the excited states at much higher temperatures, indicating a stronger exchange coupling than is observed in this case. − …”

Section: Discussionmentioning

confidence: 99%

“…The failure to observe a resolved EPR signal corresponding to an Fe III Fe II species except at very low (<2 K) temperature is somewhat unusual: antiferromagnetically coupled Fe III Fe II systems typically exhibit EPR spectra with g eff < 2, and spectra have been observed in both complexes ,− and in a range of enzymes, ,− including mammalian PAPs. ,− However, similar phenoxo-bridged Fe III Fe II complexes , also display no or unresolved EPR signals at low temperatures. This may be attributed to the fact that the exchange interaction J and the ZFS parameter D of the Fe II ion are of similar magnitude.…”

Section: Discussionmentioning

confidence: 99%

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Spectroscopic and Catalytic Characterization of a Functional Fe^IIIFe^II Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Smith

Peralta²,

Jovito³

et al. 2012

Inorg. Chem.

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A mixed-valence complex, [Fe(III)Fe(II)L1(μ-OAc)(2)]BF(4)·H(2)O, where the ligand H(2)L1 = 2-{[[3-[((bis(pyridin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzyl](pyridin-2-ylmethyl)amino]methyl]phenol}, has been studied with a range of techniques, and, where possible, its properties have been compared to those of the corresponding enzyme system purple acid phosphatase. The Fe(III)Fe(II) and Fe(III)(2) oxidized species were studied spectroelectrochemically. The temperature-dependent population of the S = 3/2 spin states of the heterovalent system, observed using magnetic circular dichroism, confirmed that the dinuclear center is weakly antiferromagnetically coupled (H = -2JS(1)·S(2), where J = -5.6 cm(-1)) in a frozen solution. The ligand-to-metal charge-transfer transitions are correlated with density functional theory calculations. The Fe(III)Fe(II) complex is electron paramagnetic resonance (EPR)-silent, except at very low temperatures (<2 K), because of the broadening caused by the exchange coupling and zero-field-splitting parameters being of comparable magnitude and rapid spin-lattice relaxation. However, a phosphate-bound Fe(III)(2) complex showed an EPR spectrum due to population of the S(tot) = 3 state (J= -3.5 cm(-1)). The phosphatase activity of the Fe(III)Fe(II) complex in hydrolysis of bis(2,4-dinitrophenyl)phosphate (k(cat.) = 1.88 × 10(-3) s(-1); K(m) = 4.63 × 10(-3) mol L(-1)) is similar to that of other bimetallic heterovalent complexes with the same ligand. Analysis of the kinetic data supports a mechanism where the initiating nucleophile in the phosphatase reaction is a hydroxide, terminally bound to Fe(III). It is interesting to note that aqueous solutions of [Fe(III)Fe(II)L1(μ-OAc)(2)](+) are also capable of protein cleavage, at mild temperature and pH conditions, thus further expanding the scope of this complex's catalytic promiscuity.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Spectroscopic and Catalytic Characterization of a Functional Fe^IIIFe^II Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Smith

Peralta²,

Jovito³

et al. 2012

Inorg. Chem.

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“…Nonheme mononuclear iron-dependent enzymes catalyze a broadvariety of reactions, including hydroxylation and halogenation of alkanes, cis-dihydroxylation and epoxidation of alkenes, aromatic ring cleavage, oxidative cyclizations, and desaturations (Koehntop et al, 2005;Mitić, Schenk, & Hanson, 2009). Such enzymes are involved in a range of biological processes including the metabolism of amino acids, nucleic acids and fatty acids, the bacterial degradation of aromatic compounds in aerobic environments, the posttranslational modification of proteins, and the biosynthesis of a wide range of bioactive natural products (Axcell & Geary, 1975;Kappock & Caradonna, 1996;Que & Ho, 1996).…”

Section: Introductionmentioning

confidence: 99%

Oxidative Tailoring Reactions Catalyzed by Nonheme Iron-Dependent Enzymes

Sydor¹,

Challis²

2012

Methods in Enzymology

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“…Examples of binuclear non-heme iron proteins include the soluble di-iron-carboxylate enzymes, that perform hydroxilation reactions (methane monooxygenase, MMO; toluene monooxygenase), desaturation (soluble stearoyl-ACP desaturases), and reduction (ribonucleotide reductase) among others (Mitić et al 2009;Nordlund and Eklund, 1995). Another well-known group of binuclear non-heme iron proteins are the Integral Membrane Histidine Motif-containing Enzymes (IMHME).…”

Section: Introductionmentioning

confidence: 99%

Phylogenomic analysis of integral diiron membrane histidine motif-containing enzymes in ciliates provides insights into their function and evolutionary relationships

Cid

Granel

Montes

et al. 2017

Molecular Phylogenetics and Evolution

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The Integral Membrane Histidine Motif-containing Enzymes (IMHME) are a class of binuclear non-heme iron proteins widely distributed among prokaryotes and eukaryotes. They are characterized by a conserved tripartite motif consisting of eight to ten histidine residues. Their known function is the activation of the dioxygen moiety to serve as efficient catalysts for reactions of hydroxylation, desaturation or reduction. To date most studies on IMHME were carried out in metazoan, phototrophic or parasitic organisms, whereas genome-wide analysis in heterotrophic free living protozoa, such as the Ciliophora phylum, has not been undertaken. In the seven fully sequenced genomes available we retrieved 118 putative sequences of the IMHME type, albeit with large differences in number among the ciliates: 11 sequences in Euplotes octocarinatus, 7 in Ichthyophthirius multifiliis, 13 in Oxytricha trifallax, 18 in Stylonychia lemnae, 25 in Tetrahymena thermophila, 31 in Paramecium tetraurelia and 13 in Pseudocohnilembus persalinus. The pool of putative sequences was classified in 16 orthologous groups from which 11 were related to fatty acid desaturase (FAD) and 5 to the fatty acid hydroxylase (FAH) superfamilies. Noteworthy, a large diversity on the number and type of FAD / FAH proteins were found among the ciliates, a feature that, in principle, may be attributed to peculiarities of the evolutionary process, such as gene expansion and reduction, but also to horizontal gene transfer, as we demonstrate in this work. We identified twelve putative enzymatic activities, from which four were newly assigned activities: sphingolipid Δ4-desaturase, ω3/Δ15 fatty acid desaturase, a large group of alkane 1-monooxygenases, and acylamide-delta-3(E)-desaturase, although unequivocal allocation would require additional experiments. We also combined the phylogenetics analysis with lipids analysis, thereby allowing the detection of two enzymatic activities not previously reported: a C-5 sterol desaturase in P. tetraurelia and a delta-9 fatty acid desaturase in Cohnilembus reniformis. The analysis revealed a significant lower number of FAD's sequences in the spirotrichea ciliates than in the oligohymenophorea, emphasizing the importance of fatty acids trophic transfer among aquatic organisms as a source of variation in metabolic activity, individual and population growth rates, and reproduction.

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Binuclear Non-Heme Iron Enzymes

Cited by 4 publications

References 620 publications

Spectroscopic and Catalytic Characterization of a Functional Fe^IIIFe^II Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Spectroscopic and Catalytic Characterization of a Functional Fe^IIIFe^II Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Oxidative Tailoring Reactions Catalyzed by Nonheme Iron-Dependent Enzymes

Phylogenomic analysis of integral diiron membrane histidine motif-containing enzymes in ciliates provides insights into their function and evolutionary relationships

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Binuclear Non-Heme Iron Enzymes

Cited by 4 publications

References 620 publications

Spectroscopic and Catalytic Characterization of a Functional FeIIIFeII Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Spectroscopic and Catalytic Characterization of a Functional FeIIIFeII Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Oxidative Tailoring Reactions Catalyzed by Nonheme Iron-Dependent Enzymes

Phylogenomic analysis of integral diiron membrane histidine motif-containing enzymes in ciliates provides insights into their function and evolutionary relationships

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Spectroscopic and Catalytic Characterization of a Functional Fe^IIIFe^II Biomimetic for the Active Site of Uteroferrin and Protein Cleavage

Spectroscopic and Catalytic Characterization of a Functional Fe^IIIFe^II Biomimetic for the Active Site of Uteroferrin and Protein Cleavage