A dinuclear zinc(II) complex of a new unsymmetric ligand with an N5O2 donor set; A structural and functional model for the active site of zinc phosphoesterases.

A dinuclear zinc(II) complex of a new unsymmetric ligand with an N5O2 donor set; A structural and functional model for the active site of zinc phosphoesterases. J Inorg Biochem. 2013 Aug 14; Authors: Das B, Daver H, Pyrkosz-Bulska M, Persch E, Barman SK, Mukherjee R, Gumienna-Kontecka E, Jarenmark M, Himo F, Nordlander E Abstract The dinuclear complex [Zn2(DPCPMP)(pivalate)](ClO4), where DPCPMP is the new unsymmetrical ligand [2-(N-(3-((bis((pyridin-2-yl)methyl)amino)methyl)-2-hydroxy-5-methylbenzyl)-N-((pyridin-2-yl)methyl)amino)acetic acid], has been synthesized and characterized. The complex is a functional model for zinc phosphoesterases with dinuclear active sites. The hydrolytic efficacy of the complex has been investigated using bis-(2,4-dinitrophenyl)phosphate (BDNPP), a DNA analog, as substrate. Speciation studies using potentiometric titrations have been performed for both the ligand and the corresponding dizinc complex to elucidate the formation of the active hydrolysis catalyst; it reveals that the dinuclear zinc(II) complexes, [Zn2(DPCPMP)](2+) and [Zn2(DPCPMP)(OH)](+) predominate the solution above pH4. The relatively high pKa of 8.38 for water deprotonation suggests that a terminal hydroxide complex is formed. Kinetic investigations of BDNPP hydrolysis over the pH range 5.5-11.0 and with varying metal to ligand ratio (metal salt:ligand=0.5:1 to 3:1) have been performed. Variable temperature studies gave the activation parameters...
Source: Journal of Inorganic Biochemistry - Category: Biochemistry Authors: Tags: J Inorg Biochem Source Type: research