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A New Heterobinuclear FeIIICuII Complex with a Single Terminal FeIII–O(phenolate) Bond. Relevance to Purple Acid Phosphatases and Nucleases

Lanznaster, Mauricio and Neves, Ademir and Bortoluzzi, Adailton J. and Aires, Veronika V. E. and Szpoganicz, Bruno and Terenzi, Hernan and Cardoso Severino, Patricia and Fuller, Julie M. and Drew, Simon C. and Gahan, Lawrence R. and Hanson, Graeme R. and Riley, Mark J. and Schenk, Gerhard (2005) A New Heterobinuclear FeIIICuII Complex with a Single Terminal FeIII–O(phenolate) Bond. Relevance to Purple Acid Phosphatases and Nucleases. Journal of Biological Inorganic Chemistry, 10 (4). pp. 319-332. ISSN 0949-8257

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Abstract

A novel heterobinuclear mixed valence complex [FeIIICuII (BPBPMP)(OAc)2]ClO4, 1, with the unsymmetrical N5O2 donor ligand 2-bis[{(2-pyridylmethyl)aminomethyl}-6-{(2- hydroxybenzyl)(2-pyridylmethyl)}aminomethyl]-4-methylphenol (H2BPBPMP) has been synthesized and characterized. A combination of data from mass spectrometry, potentiometric titrations, X-ray absorption and electron paramagnetic resonance spectroscopy, as well as kinetics measurements indicates that in ethanol/water solutions an [FeIII–(μ)OH–CuIIOH2]+ species is generated which is the likely catalyst for 2,4-bis(dinitrophenyl)phosphate and DNA hydrolysis. Insofar as the data are consistent with the presence of an FeIII-bound hydroxide acting as a nucleophile during catalysis, 1 presents a suitable mimic for the hydrolytic enzyme purple acid phosphatase. Notably, 1 is significantly more reactive than its isostructural homologues with different metal composition (FeIIIMII, where MII is ZnII, MnII, NiII, or FeII). Of particular interest is the observation that cleavage of double-stranded plasmid DNA occurs even at very low concentrations of 1 (2.5 μM), under physiological conditions (optimum pH of 7.0), with a rate enhancement of 2.7×107 over the uncatalyzed reaction. Thus, 1 is one of the most effective model complexes to date, mimicking the function of nucleases.

Item Type: Article
Additional Information: Postprint version of original published article. The original article is available at http://dx.doi.org/10.1007/s00775-005-0635-7
Keywords: heterobinuclear FeIIICuII complex; purple acid phosphatase; phosphate diester hydrolysis; DNA cleavage; EPR; XAS;
Subjects: Science & Engineering > Chemistry
Item ID: 3667
Depositing User: Gary Schenk
Date Deposited: 16 May 2012 15:43
Journal or Publication Title: Journal of Biological Inorganic Chemistry
Publisher: Springer Verlag
Refereed: Yes
URI:

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