Cooperative Transformations of Small Molecules at a Dinuclear Nickel(II) Site

Meyer, Franc; Kaifer, Elisabeth; Kircher, Peter; Heinze, Katja; Pritzkow, Hans

doi:10.1002/(sici)1521-3765(19990503)5:5<1617::aid-chem1617>3.0.co;2-b

Cited by 128 publications

(91 citation statements)

References 21 publications

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“…Nordlander et al proposed that asymmetric complexes are not only more appropriate functional models for the active site of phosphoesterase enzymes, but also that they exhibit enhanced catalytic rates compared with their symmetric counterparts. 15,19,20 Examples include ligands employed to generate PAP, 19,21,23,24,28,[96][97][98][99][100] phosphoesterase, 101 urease, 102,103 catechol oxidase 104 and manganese catalase biomimetics. 105,106 Some ligands generate a hard and a soft coordination site for the generation of heterodinuclear model complexes for PAP metalloenzymes.…”

Section: Biomimetics Of Dinuclear Metallohydrolasesmentioning

confidence: 99%

Spectroscopic and mechanistic studies of dinuclear metallohydrolases and their biomimetic complexes

et al. 2014

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An enhanced understanding of the metal ion binding and active site structural features of phosphoesterases such as the glycerophosphodiesterase from Enterobacter aerogenes (GpdQ), and the organophosphate degrading agent from Agrobacterium radiobacter (OpdA) have important consequences for potential applications. Coupled with investigations of the metalloenzymes, programs of study to synthesise and characterise model complexes based on these metalloenzymes can add to our understanding of structure and function of the enzymes themselves. This review summarises some of our work and illustrates the significance and contributions of model studies to knowledge in the area.

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Section: Biomimetics Of Dinuclear Metallohydrolasesmentioning

confidence: 99%

Spectroscopic and mechanistic studies of dinuclear metallohydrolases and their biomimetic complexes

et al. 2014

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“…Of functional significance, this species reacts with ethanol to generate ethyl carbamate. For the second representative example, a pyrazolate-based ligand (HL2) was used to synthesize the crystallographically characterized L 2 Ni 2 (O 2 H 3 )(ClO 4 ) 2 species 37. The addition of urea leads to the displacement of H 3 O 2 and bidentate binding with the carbonyl oxygen coordinating to one nickel and an amine binding to the second.…”

Section: 0 Role Of Nickel In Ureasementioning

confidence: 99%

Interplay of metal ions and urease

et al. 2009

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Summary Urease, the first enzyme to be crystallized, contains a dinuclear nickel metallocenter that catalyzes the decomposition of urea to produce ammonia, a reaction of great agricultural and medical importance. Several mechanisms of urease catalysis have been proposed on the basis of enzyme crystal structures, model complexes, and computational efforts, but the precise steps in catalysis and the requirement of nickel versus other metals remain unclear. Purified bacterial urease is partially activated via incubation with carbon dioxide plus nickel ions; however, in vitro activation also has been achieved with manganese and cobalt. In vivo activation of most ureases requires accessory proteins that function as nickel metallochaperones and GTP-dependent molecular chaperones or play other roles in the maturation process. In addition, some microorganisms control their levels of urease by metal ion-dependent regulatory mechanisms.

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“…It is operative in various plants and microorganisms and plays important roles in (7) 171.44 (13) O(1)-Ni-N(4) 93.35 (7) 93.31 ( [44][45][46][47][48][49][50][51], and many dinickel urea adducts have been reported as structural models [44,[50][51][52]. However, to date, there is no report on the use of dinickel complexes as functional models for this enzyme, and few examples are known to convert urea to cyanate [53][54][55]. The first case of this reaction at a dinuclear core was provided by Uozumi and co-workers [53].…”

Section: Study Of Reactivity Of Urea With 1-3mentioning

confidence: 99%

Dinuclear nickel(II) complexes with Schiff base ligands: syntheses, structures and bio-relevant catalytic activities

Banerjee

Guha

Maiti

et al. 2011

Transition Met Chem

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3 ] (3), (where L 1 = 2,6-bis(N-ethylpyrrolidineiminomethyl)-4-methylphenolato, L 2 = 2,6-bis(N-ethylpiperidineiminomethyl)-4-methylphenolato and L 3 = 2,6-bis{N-ethyl-N-(3-hydroxypropyl iminomethyl)}-4-methylphenolato), have been synthesized and structurally characterized by X-ray single-crystal diffraction in addition to routine physicochemical techniques. Density functional theory calculations have been performed to understand the nature of the electronic spectra of the complexes. Complexes 1-3 when reacted with 4-nitrophenyl phosphate in 50:50 acetonitrile-water medium promote the cleavage of the O-P bond to form p-nitrophenol and smoothly convert 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) either in MeOH or in MeCN medium. Phosphatase-and catecholase-like activities were monitored by UV-vis spectrophotometry and the Michaelis-Menten equation was applied to rationalize all the kinetic parameters. Upon treatment with urea, complexes 1 and 0 ) derivatives, respectively, whereas 3 remains unaltered under same reaction conditions. IntroductionBimetallic cores are found to be present at the active sites of many metalloenzymes and play essential roles in biological systems. Structural exploration has pointed out that these active sites comprise of two (homo/hetero) transition metal ions in close proximity, and research had been extensively devoted to the synthesis of dinuclear coordination compounds in order to mimic these active centers [1][2][3][4]. A simple method to attain this goal is using compartmental ligands [5][6][7][8], in which at least one atom, acting as bridging donor, is shared by the metal centers [9]. Thus, complexes with compartmental ligands have received considerable attention for their unusual, although pre-ordered properties [7, 10-13]. Among the 3d metal ions, Ni II has been widely employed for its effectiveness as a templating agent in many syntheses and for the high stability of its complexes in solution [14]. Although nickel is recognized as an essential trace element for bacteria, plants, animals and also, recently, humans [15][16][17][18][19][20], the role of this metal in animal biochemistry remains unclear. To date, urease, glyoxylase I, acireductone dioxygenase, superoxide dismutase, methyl-CoM reductase, hydrogenase, carbon monoxide dehydrogenase and acetyl-CoA Electronic supplementary material The online version of this article (

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Cooperative Transformations of Small Molecules at a Dinuclear Nickel(II) Site

Cited by 128 publications

References 21 publications

Spectroscopic and mechanistic studies of dinuclear metallohydrolases and their biomimetic complexes

Spectroscopic and mechanistic studies of dinuclear metallohydrolases and their biomimetic complexes

Interplay of metal ions and urease

Dinuclear nickel(II) complexes with Schiff base ligands: syntheses, structures and bio-relevant catalytic activities

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