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Polyoxomolybdate promoted hydrolysis of a DNA-model phosphoester studied by NMR and EXAFS spectroscopy

Gregory Absillis, Rik Van Deun UGent and Tatjana N Parac-Vogt (2011) INORGANIC CHEMISTRY. 50(22). p.11552-11560
abstract
Hydrolysis of (p-nitrophenyl)phosphate (NPP), a commonly used phosphatase model substrate, was examined in molybdate solutions by means of (1)H, (31)P, and (95)Mo NMR spectroscopy and Mo K-edge Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. At 50 degrees C and pD 5.1 the cleavage of the phosphoester bond in NPP proceeds with a rate constant of 2.73 x 10(-5) s(-1) an acceleration of nearly 3 orders of magnitude as compared to the hydrolysis measured in the absence of molybdate. The pD dependence of k(obs) exhibits a bell-shaped profile, with the fastest cleavage observed in solutions where [Mo(7)O(24)](6-) is the major species in solution. Mixing of NPP and [Mo(7)O(24)](6-) resulted in formation of these two intermediate complexes that were detected by (31)P NMR spectroscopy. Complex A was characterized by a (31)P NMR resonance at -4.27 ppm and complex B was characterized by a (31)P NMR resonance at -7.42 ppm. On the basis of the previous results from diffusion ordered NMR spectroscopy, performed with the hydrolytically inactive substrate phenylphosphonate (PhP), the structure of these two complexes was deduced to be (NPP)(2)Mo(5)O(21)(4-) (complex A) and (NPP)(2)Mo(12)O(36)(H(2)O)(6)(4-) (complex B). The pH studies point out that both complexes are hydrolytically active and lead to the hydrolysis of phosphoester bond in NPP. The NMR spectra did not show evidence of any paramagnetic species, excluding the possibility of Mo(VI) reduction to Mo(V), and indicating that the cleavage of the phosphomonoester bond is purely hydrolytic. The Mo K-edge XANES region also did not show any sign of Mo(VI) to Mo(V) reduction during the hydrolytic reaction. (95)Mo NMR and Mo K-edge EXAFS spectra measured during different stages of the hydrolytic reaction showed a gradual disappearance of [Mo(7)O(24)](6-) during the hydrolytic reaction and appearance of [P(2)Mo(5)O(23)](6-), which was the final complex observed at the end of hydrolytic reaction.
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author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
ANTITUMOR-ACTIVITY, P-31 NMR, PHOSPHATE DIESTER, METAL-IONS, IN-VITRO, COMPLEXES, CLEAVAGE, APOPTOTIC CELL-DEATH, MULTICOMPONENT POLYANIONS, PHOSPHODIESTER HYDROLYSIS
journal title
INORGANIC CHEMISTRY
Inorg. Chem.
volume
50
issue
22
pages
11552 - 11560
Web of Science type
Article
Web of Science id
000296830400037
JCR category
CHEMISTRY, INORGANIC & NUCLEAR
JCR impact factor
4.601 (2011)
JCR rank
3/43 (2011)
JCR quartile
1 (2011)
ISSN
0020-1669
DOI
10.1021/ic201498u
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
1971487
handle
http://hdl.handle.net/1854/LU-1971487
date created
2011-12-21 13:32:28
date last changed
2018-01-29 12:12:32
@article{1971487,
  abstract     = {Hydrolysis of (p-nitrophenyl)phosphate (NPP), a commonly used phosphatase model substrate, was examined in molybdate solutions by means of (1)H, (31)P, and (95)Mo NMR spectroscopy and Mo K-edge Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. At 50 degrees C and pD 5.1 the cleavage of the phosphoester bond in NPP proceeds with a rate constant of 2.73 x 10(-5) s(-1) an acceleration of nearly 3 orders of magnitude as compared to the hydrolysis measured in the absence of molybdate. The pD dependence of k(obs) exhibits a bell-shaped profile, with the fastest cleavage observed in solutions where [Mo(7)O(24)](6-) is the major species in solution. Mixing of NPP and [Mo(7)O(24)](6-) resulted in formation of these two intermediate complexes that were detected by (31)P NMR spectroscopy. Complex A was characterized by a (31)P NMR resonance at -4.27 ppm and complex B was characterized by a (31)P NMR resonance at -7.42 ppm. On the basis of the previous results from diffusion ordered NMR spectroscopy, performed with the hydrolytically inactive substrate phenylphosphonate (PhP), the structure of these two complexes was deduced to be (NPP)(2)Mo(5)O(21)(4-) (complex A) and (NPP)(2)Mo(12)O(36)(H(2)O)(6)(4-) (complex B). The pH studies point out that both complexes are hydrolytically active and lead to the hydrolysis of phosphoester bond in NPP. The NMR spectra did not show evidence of any paramagnetic species, excluding the possibility of Mo(VI) reduction to Mo(V), and indicating that the cleavage of the phosphomonoester bond is purely hydrolytic. The Mo K-edge XANES region also did not show any sign of Mo(VI) to Mo(V) reduction during the hydrolytic reaction. (95)Mo NMR and Mo K-edge EXAFS spectra measured during different stages of the hydrolytic reaction showed a gradual disappearance of [Mo(7)O(24)](6-) during the hydrolytic reaction and appearance of [P(2)Mo(5)O(23)](6-), which was the final complex observed at the end of hydrolytic reaction.},
  author       = {Absillis, Gregory and Van Deun, Rik and Parac-Vogt, Tatjana N},
  issn         = {0020-1669},
  journal      = {INORGANIC CHEMISTRY},
  keyword      = {ANTITUMOR-ACTIVITY,P-31 NMR,PHOSPHATE DIESTER,METAL-IONS,IN-VITRO,COMPLEXES,CLEAVAGE,APOPTOTIC CELL-DEATH,MULTICOMPONENT POLYANIONS,PHOSPHODIESTER HYDROLYSIS},
  language     = {eng},
  number       = {22},
  pages        = {11552--11560},
  title        = {Polyoxomolybdate promoted hydrolysis of a DNA-model phosphoester studied by NMR and EXAFS spectroscopy},
  url          = {http://dx.doi.org/10.1021/ic201498u},
  volume       = {50},
  year         = {2011},
}

Chicago
Absillis, Gregory, Rik Van Deun, and Tatjana N Parac-Vogt. 2011. “Polyoxomolybdate Promoted Hydrolysis of a DNA-model Phosphoester Studied by NMR and EXAFS Spectroscopy.” Inorganic Chemistry 50 (22): 11552–11560.
APA
Absillis, G., Van Deun, R., & Parac-Vogt, T. N. (2011). Polyoxomolybdate promoted hydrolysis of a DNA-model phosphoester studied by NMR and EXAFS spectroscopy. INORGANIC CHEMISTRY, 50(22), 11552–11560.
Vancouver
1.
Absillis G, Van Deun R, Parac-Vogt TN. Polyoxomolybdate promoted hydrolysis of a DNA-model phosphoester studied by NMR and EXAFS spectroscopy. INORGANIC CHEMISTRY. 2011;50(22):11552–60.
MLA
Absillis, Gregory, Rik Van Deun, and Tatjana N Parac-Vogt. “Polyoxomolybdate Promoted Hydrolysis of a DNA-model Phosphoester Studied by NMR and EXAFS Spectroscopy.” INORGANIC CHEMISTRY 50.22 (2011): 11552–11560. Print.