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Engineering sensitive glutathione transferase for the detection of xenobiotics

Kapoli, P., Axarli, I. A., Platis, D., Fragoulaki, M., Paine, Mark ORCID: https://orcid.org/0000-0003-2061-7713, Hemingway, Janet ORCID: https://orcid.org/0000-0002-3200-7173, Vontas, John and Labrou, N. E. (2008) 'Engineering sensitive glutathione transferase for the detection of xenobiotics'. Biosensors & Bioelectronics, Vol 24, Issue 3, pp. 498-503.

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Abstract

Cytosolic glutathione transferases (GSTs) are a major reserve of high-capacity ligand binding Proteins which recognise a large variety of hydrophobic compounds. In the present study, the binding of non-substrate xenobiotic compounds (herbicides and insecticides) to maize CST I was investigated by employing kinetic inhibition studies, site-directed mutagenesis and molecular modelling studies. The results showed that the xenobiotics bind at the substrate binding site. Based on in silico docking analysis, two residues were selected for assessing their contribution to xenobiotic binding. The mutant GIn53Ala of GST I Exhibits 9.2-fold higher inhibition potency for the insecticide malathion, compared to the wild-type enzyme. A potentiometric assay was developed for the determination of malathion using the GIn53Ala mutant enzyme. The assay explores the ability of the xenobiotic to promote inhibition of the GST-catalysing 1-chloro-2,4-dinitrobenzene (CDNB)/glutathione (GSH) conjugation reaction. The sensing scheme is based on the pH change occurring in a low buffer system by the GST reaction, which is measured potentiometrically using a pH electrode. Calibration curve was obtained for malathion,with useful concentration range 0-20 mu M. The method's reproducibility was in the order of +/- 3-5% and malathion recoveries were 96.7 +/- 2.8%. Immobilized GIn53Ala mutant GST was used to assemble a biosensor for malathion. The enzyme was immobilized by crosslinking with glutaraldehyde and trapped behind a semipermeable membrane in front of the pH electrode. The results demonstrated that the immobilized enzyme behaved similar to free enzyme. (C) 2008 Elsevier B.V. All rights reserved.

Item Type: Article
Additional Information: Funding: This work was supported by grants from AUA (Code No: 020083) and from the Innovative Vector Control Consortium (IVCC) (M.P., J.H., J.V., and N.L.). I.A. gratefully acknowledges A.S. Onassis Public Benefit Foundation for financial support.
Uncontrolled Keywords: glutathione transferase ligandin binding site malathion potentiometric assay xenobiotics active-site architecture s-transferase ligandin function arabidopsis-thaliana binding-site a1-1 residues complex stability evolution
Subjects: QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control
WA Public Health > Preventive Medicine > WA 240 Disinfection. Disinfestation. Pesticides (including diseases caused by)
Faculty: Department: Groups (2002 - 2012) > Vector Group
Digital Object Identifer (DOI): https://doi.org/10.1016/j.bios.2008.06.037
Depositing User: Users 183 not found.
Date Deposited: 10 Aug 2010 11:29
Last Modified: 06 Feb 2018 13:00
URI: http://archive.lstmed.ac.uk/id/eprint/824

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