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Bài báo - Tạp chí
(2013) Trang: 49
Tạp chí: 16th International Conference on BioInorganic Chemistry (ICBIC), Grenoble, FRANCE, 22-26 July 2013.
Liên kết: http://icbic16.com/

Polyoxometalates (POMs) are early transition metal (M = V, Nb, Ta, Mo and W in their highest oxidation state) oxygen anion clusters. Several classes of POMs have been reported to have potent anti-tumor, anti-viral and anti-bacterial properties, resulting in a substantial interest in the potential medicinal application of POMs. Several studies were recently made on the hydrolysis of DNA- and RNA-model substrates by using the isopolyoxometalates [Mo7O246-]1 as well as a Zr(IV)-substituted Wells-Dawson type POM2 as artificial phosphatases. Phosphodiester bonds form the backbone of DNA and RNA macromolecules and are extremely resistant towards hydrolysis. The half-life for spontaneous phosphoester bond hydrolysis has been estimated to be higher than 100 000 years for DNA and 4 years for RNA at neutral pH and 25 °C. Despite the extreme stability of the phosphoester bond, its efficient cleavage is a required procedure in biochemical fields. In nature phosphatases are responsible for hydrolyzing phosphodiester bonds with impressive rate enhancements. In our quest to understand the biological role of POM anions on a molecular level, the phosphoesterase activity of a bimetal-substituted [α-PW11O39]7- Keggin type POM is examined.





In this study we report the first example of phosphoester bond hydrolysis promoted by a binuclear Zr(IV)-substituted Keggin POM, [{α-PW11O39Zr(µ-OH)(H2O)}2]8- (ZrK 2:2), as a new artificial phosphatase. The speciation of ZrK 2:2, which is highly dependent on the pD, concentration, and temperature, was fully determined by mean of 31P NMR spectroscopy. The hydrolytic activity of ZrK 2:2 towards the phosphoester bond in bis-4-nitrophenyl phosphate (BNPP), a commonly used DNA model substrate, was examined by means of 1H and 31P NMR spectroscopy. The mechanism of BNPP hydrolysis was established by 1H, 31P, DOSY, NOESY NMR spectroscopy.


Các bài báo khác
(2013) Trang: 61
Tạp chí: 12th Young Belgian Magnetic Resonance Scientist (YBMRS), Blankenberge, Belgium, 02-03 December 2013

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