Dinuclear Iron‐ and Manganese‐Oxo Sites in Biology

Que, Lawrence; True, Anne E.

doi:10.1002/9780470166390.ch3

Cited by 282 publications

(22 citation statements)

References 301 publications

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“…Crystallized Fe III -IDA at pH 7.0 contained a l-oxo bridged dimer iron according to X-ray magnetic susceptibility analyses. From solution UV-Vis absorption spectrum analysis, Fe III -IDA had almost the same spectrum as Fe III -NTA, and showed the same absorption at around 440 nm with a shoulder at 480 nm ( Figure 6A), which was assigned to a charge-transfer transition from the l-oxo ligands to a d orbital of Fe III (Donald et al 1990;Que et al 1990). Around neutral pH, ESR signals were silent, indicating the presence of a dimer structure of Fe III -IDA, and anti-ferromagnetism (Carl et al 1995).…”

Section: Discussionmentioning

confidence: 94%

Oxidative renal tubular injuries induced by aminocarboxylate-type iron (III) coordination compounds as candidate renal carcinogens

et al. 2006

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Oxidative renal tubular injuries and carcinogenesis induced by Fe(III)-nitrilotriacetate (NTA) and Fe(III)-ethylenediamine-N,N'-diacetate (EDDA) have been reported in rodent kidneys, but the identity of iron coordination structure essential for renal carcinogenesis, remains to be clarified. We compared renal tubular injuries caused by various low molecular weight aminocarboxylate type chelators with injuries due to NTA and EDDA. We found that Fe(III)-iminodiacetate (IDA), a novel iron-chelator, induced acute tubular injuries and lipid peroxidation to the same extent. We also prepared Fe(III)-IDA solutions at different pHs, and studied resultant oxidative injuries and physicochemical properties. The use of Fe(III)-IDA at pH 5.2, 6.2, and 7.2 resulted in renal tubular necrosis and apoptotic cell death, but neither tubular necrosis nor apoptosis was observed at pH 8.2. Spectrophotometric data suggested that Fe(III)-IDA had the same dimer structure from pH 6.2 to 7.2 as Fe(III)-NTA; but at a higher pH, iron polymerized and formed clusters. Fe(III)-IDA was crystallized, and this was confirmed by X-ray analysis and magnetic susceptibility measurements. These data indicated that Fe(III)-IDA possessed a linear mu-oxo bridged dinuclear iron (III) around neutral pH.

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Section: Discussionmentioning

confidence: 94%

Oxidative renal tubular injuries induced by aminocarboxylate-type iron (III) coordination compounds as candidate renal carcinogens

et al. 2006

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“…AtPAP15 represents one of the 29 Arabidopsis PAPs (AtPAP1-AtPAP29) that form the metallophosphatase family, enzymes that contain a dinuclear center in their active site (Que and True, 1990;Vincent et al, 1991;Li et al, 2002). PAPs have been shown in vitro to nonspecifically catalyze the release of phosphate from numerous phosphate esters and anhydrides at a pH range of 4 to 7 (Klabunde et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

An Arabidopsis Purple Acid Phosphatase with Phytase Activity Increases Foliar Ascorbate

et al. 2007

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Ascorbate (AsA) is the most abundant antioxidant in plant cells and a cofactor for a large number of key enzymes. However, the mechanism of how AsA levels are regulated in plant cells remains unknown. The Arabidopsis (Arabidopsis thaliana) activationtagged mutant AT23040 showed a pleiotropic phenotype, including ozone resistance, rapid growth, and leaves containing higher AsA than wild-type plants. The phenotype was caused by activation of a purple acid phosphatase (PAP) gene, AtPAP15, which contains a dinuclear metal center in the active site. AtPAP15 was universally expressed in all tested organs in wild-type plants. Overexpression of AtPAP15 with the 35S cauliflower mosaic virus promoter produced mutants with up to 2-fold increased foliar AsA, 20% to 30% decrease in foliar phytate, enhanced salt tolerance, and decreased abscisic acid sensitivity. Two independent SALK T-DNA insertion mutants in AtPAP15 had 30% less foliar AsA and 15% to 20% more phytate than wild-type plants and decreased tolerance to abiotic stresses. Enzyme activity of partially purified AtPAP15 from plant crude extract and recombinant AtPAP15 expressed in bacteria and yeast was highest when phytate was used as substrate, indicating that AtPAP15 is a phytase. Recombinant AtPAP15 also showed enzyme activity on the substrate myoinositol-1-phosphate, indicating that the AtPAP15 is a phytase that hydrolyzes myoinositol hexakisphosphate to yield myoinositol and free phosphate. Myoinositol is a known precursor for AsA biosynthesis in plants. Thus, AtPAP15 may modulate AsA levels by controlling the input of myoinositol into this branch of AsA biosynthesis in Arabidopsis.

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“…Transition metal complexes with Schiff-base ligand containing the carboxylate group have been of great interest due to their importance as essentially biologically active [1][2][3] models for metalloproteins [4] and their various geometry aspects [5]. Metals bound to amino acids are essential for the catalytic function of certain enzymes, and their chemistry has received a great deal of research interest due to their significant interaction with enzymes and with different organic ligands which enables a better understanding of the antitumor/viral activities of this class of compounds and for modeling substrates involved in enzyme inhibition [6,7].…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure of [Bis(L-Alaninato)Diaqua]Nickel(II) Dihydrate

Khatib

Aqra

Deamer

et al. 2009

Research Letters in Inorganic Chemistry

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The title complex, [Ni(C 3 H 6 O 2 N) 2 (H 2 O) 2 ]·2H 2 O, has been prepared from nickel(II) chloride in aqueous solution by adding L-alanine and potassium hydroxide. It has been crystallized from aqueous solution, and its structure was determined by X-ray structure analysis. The nickel(II) ion adopts distorted octahedral coordination geometry with two bidentate L-alanine molecules and two water molecules. The complex is neutral and dihydrated. The crystal structure shows the hydrogen bonding between water and amide hydrogens within the lattice, and each fragment of the complex contains two water molecules as hydrated water. The L-alaninato ligand skeleton of the compound adopts the most stable trans-III configuration in the solid state. The alternating two five-membered chelate rings are in the stable gauche conformation.

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Dinuclear Iron‐ and Manganese‐Oxo Sites in Biology

Cited by 282 publications

References 301 publications

Oxidative renal tubular injuries induced by aminocarboxylate-type iron (III) coordination compounds as candidate renal carcinogens

Oxidative renal tubular injuries induced by aminocarboxylate-type iron (III) coordination compounds as candidate renal carcinogens

An Arabidopsis Purple Acid Phosphatase with Phytase Activity Increases Foliar Ascorbate

Crystal Structure of [Bis(L-Alaninato)Diaqua]Nickel(II) Dihydrate

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