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001-es BibID:	BIBFORM085216
Első szerző:	Bauer-Siebenlist, Bernhard
Cím:	Effect of Zn...Zn Separation on the Hydrolytic Activity of Model Dizinc Phosphodiesterases / Bernhard Bauer-Siebenlist, Franc Meyer, Etelka Farkas, Denis Vidovic, Sebastian Dechert
Dátum:	2005
ISSN:	0947-6539 1521-3765
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk bioinorganic chemistry dinuclear complexes phosphatase models pyrazolate ligands zinc complexes
Megjelenés:	Chemistry-A European Journal. - 11 : 15 (2005), p. 4349-4360. -
További szerzők:	Meyer, Franc Farkas Etelka (1948-) (vegyész) Vidovic, Denis Dechert, Sebastian
Pályázati támogatás:	OTKA TS 040685 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM084872
Első szerző:	Bauer-Siebenlist, Bernhard
Cím:	Correlation of Structure and Function in Oligonuclear Zinc(II) Model Phosphatases / Bernhard Bauer-Siebenlist, Franc Meyer, Etelka Farkas, Denis Vidovic, Jose Antonio Cuesta-Seijo, Regine Herbst-Irmer, Hans Pritzkow
Dátum:	2004
ISSN:	0020-1669 1520-510X
Megjegyzések:	A series of pyrazolate-based dizinc(II) complexes has been synthesized and investigated as functional models for phosphoesterases, focusing on correlations between hydrolytic activity and molecular parameters of the bimetallic core. The Zn···Zn distance, the (bridging or nonbridging) position of the Zn-bound hydroxide nucleophile, and individual metal ion coordination numbers are controlled by the topology of the compartmental ligand scaffold. Species distributions of the various dizinc complexes in solution have been determined potentiometrically, and structures in the solid state have been elucidated by X-ray crystallography. The hydrolysis of bis(p-nitrophenyl)phosphate (BNPP) promoted by the dinuclear phosphoesterase model complexes has been investigated in DMSO/buffered water (1:1) at 50 °C as a function of complex concentration, substrate concentration, and pH. Coordination of the phosphodiester has been followed by ESI mass spectrometry, and bidentate binding could be verified crystallographically in two cases. Drastic differences in hydrolytic activity are observed and can be attributed to molecular properties. A significant decrease of the pKa of zinc-bound water is observed if the resulting hydroxide is involved in a strongly hydrogen-bonded intramolecular O2H3 bridge, which can be even more pronounced than for a bridging hydroxide. Irrespective of the pKa of the Zn-bound water, a hydroxide in a bridging position evidently is a relatively poor nucleophile, while a nonbridging hydroxide position is more favorable for hydrolytic activity. Additionally, the metal array has to provide a sufficient number of coordination sites for activating both the substrate and the nucleophile, where phosphate diesters such as BNPP preferentially bind in a bidentate fashion, requiring a third site for water binding. Product inhibition of the active site by the liberated (p-nitrophenyl)phosphate is observed, and the product-inhibited complex could be characterized crystallographically. In that complex, the phosphate monoester is found to cap a rectangular array of four zinc ions composed of two bimetallic entities.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry. - 43 : 14 (2004), p. 4189-4202. -
További szerzők:	Meyer, Franc Farkas Etelka (1948-) (vegyész) Vidovic, Denis Cuesta-Seijo, Jose Antonio Herbst-Irmer, Regine Pritzkow, Hans
Pályázati támogatás:	OTKA TS 040685 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM006211
Első szerző:	Müller, Holger
Cím:	New pyrazole-based ligands with two tripodal binding pockets : potential scaffolds for metallobiosite modeling / Muller, H., Bauer-Siebenlist, B., Csapo, E., Dechert, S., Farkas, E., Meyer, F.
Dátum:	2008
ISSN:	0020-1669
Megjegyzések:	The synthesis of a new set of bioinspired dinucleating ligand scaffolds HL1-HL3 based on a bridging pyrazolate with appended chelate arms is reported. The ligands provide two binding compartments akin to the tris(imidazolyl)methane motif, predisposed to act as facially tridentate coordination caps. Potentiometric titrations of HL1 in the presence of Ni2+ and Zn2+ reveal formation of species with a metal:ligand ratio 1:1 in aqueous solution, and UV-vis data for the Ni-II system suggest that the complex [(L2Ni2)-Ni-1](2+) with {NiN6} chromophore is formed under appropriate pH conditions. In contrast, trinickel(II) complexes [(L2Ni3)-Ni-2(NO3)(4)(MeOH)(2)] (4) and [(L2Ni3Cl2)-Ni-2(MeOH)(4)]Cl-2 (5) could be obtained from MeOH solutions and characterized crystallographically. The anticipated tripodal {N-3} binding mode of the ligand is indeed realized for the central Ni-II ion, but the counteranions or MeOH solvent molecules lead to dissociation of one of the N donor legs for the outer Ni-II ions with formation of intramolecular H-bonds between a Ni-bound MeOH and the pyrazolate-N. X-ray crystals structures were also obtained for three Cu-I complexes [(L2Cu4X2)-Cu-3](PF6)(2) with X = PMe3 (6), CNnBu (7), CNC6H3Me2-2,6 (8), where all Cu-I ions are three-coordinate in a distorted trigonal-planar arrangement. The two inner metals are bound to two imidazole-N from one ligand sidearm and a pyrazolate-N from the other ligand while the outer Cu-I ions are hosted by the pyrazolate-N and one imidazole-N from the nearby sidearm with the third coordination site filled by the coligand X. Spectroscopic and ESI-MS data suggest that the trinickel complexes stay intact even in coordinating solvents while the Cu-I complexes in solution are partly dissociated into their bimetallic constituents. The solid state structures observed for the oligonuclear complexes 4-8 are reminiscent of the coordination motifs previously found for related mononuclear complexes based on tripodal tris (imidazolyl)methane, which corroborates the description of HL1-HL3 as novel binucleating versions of such tris (imidazolyl) methane ligands.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Inorganic Chemistry. - 47 : 12 (2008), p. 5278-5292. -
További szerzők:	Bauer-Siebenlist, Bernhard Csapó Edit (1983-) (vegyész) Dechert, Sebastian Farkas Etelka (1948-) (vegyész) Meyer, Franc
Internet cím:	elektronikus változat elektronikus változat
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