title: Recognition and detoxification of the insecticide DDT by Drosophila melanogaster glutathione S-transferase D1.
abstract: GSTD1 is one of several insect glutathione S-transferases capable of metabolizing the insecticide DDT. Here we use crystallography and NMR to elucidate the binding of DDT and glutathione to GSTD1. The crystal structure of Drosophila melanogaster GSTD1 has been determined to 1.1 A resolution, which reveals that the enzyme adopts the canonical GST fold but with a partially occluded active site caused by the packing of a C-terminal helix against one wall of the binding site for substrates. This helix would need to unwind or be displaced to enable catalysis. When the C-terminal helix is removed from the model of the crystal structure, DDT can be computationally docked into the active site in an orientation favoring catalysis. Two-dimensional (1)H,(15)N heteronuclear single-quantum coherence NMR experiments of GSTD1 indicate that conformational changes occur upon glutathione and DDT binding and the residues that broaden upon DDT binding support the predicted binding site. We also show that the ancestral GSTD1 is likely to have possessed DDT dehydrochlorinase activity because both GSTD1 from D. melanogaster and its sibling species, Drosophila simulans, have this activity.
authors.affiliation: Department of Genetics, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Melbourne, Victoria 3010, Australia.
authors.forename: Wai Yee
authors.initials: WY
authors.lastname: Low
authors.forename: Susanne C
authors.initials: SC
authors.lastname: Feil
authors.forename: Hooi Ling
authors.initials: HL
authors.lastname: Ng
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gorman
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Morton
authors.forename: James
authors.initials: J
authors.lastname: Pyke
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: McConville
authors.forename: Michael
authors.initials: M
authors.lastname: Bieri
authors.forename: Yee-Foong
authors.initials: YF
authors.lastname: Mok
authors.forename: Charles
authors.initials: C
authors.lastname: Robin
authors.forename: Paul R
authors.initials: PR
authors.lastname: Gooley
authors.forename: Michael W
authors.initials: MW
authors.lastname: Parker
authors.forename: Philip
authors.initials: P
authors.lastname: Batterham
mesh_terms: D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003634:DDT / Q000737:chemistry* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000201:enzymology*; D005982:Glutathione Transferase / Q000378:metabolism*; D008658:Inactivation, Metabolic; D007306:Insecticides / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D011487:Protein Conformation
chemical_list: D007306:Insecticides; D003634:DDT; D005982:Glutathione Transferase