title: A new heterobinuclear FeIIICuII complex with a single terminal FeIII-O(phenolate) bond. Relevance to purple acid phosphatases and nucleases.
abstract: A novel heterobinuclear mixed valence complex [Fe(III)Cu(II)(BPBPMP)(OAc)(2)]ClO(4), 1, with the unsymmetrical N(5)O(2) donor ligand 2-bis[{(2-pyridylmethyl)aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)}aminomethyl]-4-methylphenol (H(2)BPBPMP) 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 [Fe(III)-(mu)OH-Cu(II)OH(2)](+) 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 Fe(III)-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 (Fe(III)M(II), where M(II) is Zn(II), Mn(II), Ni(II), or Fe(II)). Of particular interest is the observation that cleavage of double-stranded plasmid DNA occurs even at very low concentrations of 1 (2.5 microM), under physiological conditions (optimum pH of 7.0), with a rate enhancement of 2.7 x 10(7) over the uncatalyzed reaction. Thus, 1 is one of the most effective model complexes to date, mimicking the function of nucleases.
authors.affiliation: LABINC Laboratório de Bioinorgânica e Cristalografia, Departamento de Química, Universidade Federal de Santa Catarina, Campus Trindade, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Lanznaster
authors.forename: Ademir
authors.initials: A
authors.lastname: Neves
authors.forename: Adailton J
authors.initials: AJ
authors.lastname: Bortoluzzi
authors.forename: Veronika V E
authors.initials: VV
authors.lastname: Aires
authors.forename: Bruno
authors.initials: B
authors.lastname: Szpoganicz
authors.forename: Hernán
authors.initials: H
authors.lastname: Terenzi
authors.forename: Patricia Cardoso
authors.initials: PC
authors.lastname: Severino
authors.forename: Julie M
authors.initials: JM
authors.lastname: Fuller
authors.forename: Simon C
authors.initials: SC
authors.lastname: Drew
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Gahan
authors.forename: Graeme R
authors.initials: GR
authors.lastname: Hanson
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Riley
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schenk
mesh_terms: D000135:Acid Phosphatase / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D003851:Deoxyribonucleases / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry
chemical_list: D006023:Glycoproteins; D009942:Organometallic Compounds; D003300:Copper; D007501:Iron; D003851:Deoxyribonucleases; C091137:purple acid phosphatase; D000135:Acid Phosphatase