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Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.49A [2010] >
IJC-A Vol.49A(08) [August 2010] >
| Title: | Structure-function mimicry of oxidized purple acid phosphatase-PAPox – A new functional model |
| Authors: | Waghmode, Shobha A
Date, Sadgopal K
Gupta, Vidya S
Rane, Sandhya Y |
| Keywords: | Bioinorganic chemistry
Nuclease activity
PAPox analogues
Iron
DNA cleavage
Antiferromagnetic exchange |
| Issue Date: | Aug-2010 |
| Publisher: | CSIR |
| IPC Code: | Int. Cl.9 C07F15/02 |
| Abstract: | Electronic structure and spectroscopic properties
of the novel diiron active site of oxidized mammalian purple acid phosphatase
analogues, Fe-6: [Fe2 ( -O) ( -OAc) (4HNSQox)∸(ONSQox)2∸(H2O)4] and Fe-7:
[Fe2 ( -O) ( -OAc)(ONSQox)2∸(OAc) (H2O)4] are described. Magnetic susceptibility SQUID data of Fe-6 are best
fitted to Heisenberg’s isotropic spin pair (S
= 5/2, 3/2) model using magnetic parameters g = 2 and J = – 36.8 cm-1 with R
factor = 6.4 × 10-4. The antiferromagnetic exchange
establishes Fe(III)-O-Fe(III) dimeric core with Fe(III) site having two radical
ligations in the naphthosemiquinone oxime form of lawsone oxime. In the model
compound Fe-7 of oxidized purple acid phosphatase, bridged and terminal acetate
functions are identified according to their different energies of activations,
i.e, ~34 and 58 kJ mol-1 respectively. Also, the reduced
naphthoquinone oxime form of ligand is characterized by its energy of
activation (~15 kJ mol-1) from pyrolytic reaction. Mössbauer
parameters,  = 0.4 mm s-1 and DEQ =
0.8 mm s-1, are characteristics of oxidized Fe(III) in high spin
octahedral site. Only Fe-6 shows analogous physiological DNA cleavage activity
on pUC19 plasmid and acts as a good model of oxidized purple acid phosphatase
enzyme. |
| Page(s): | 1023-1029 |
| Source: | IJC-A Vol.49A(08) [August 2010]
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