Recognition and detoxification of the insecticide DDT by Drosophila melanogaster glutathione S-transferase D1.
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.
Low
Wai Yee
WY
Department of Genetics, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Melbourne, Victoria 3010, Australia.
Feil
Susanne C
SC
Ng
Hooi Ling
HL
Gorman
Michael A
MA
Morton
Craig J
CJ
Pyke
James
J
McConville
Malcolm J
MJ
Bieri
Michael
M
Mok
Yee-Foong
YF
Robin
Charles
C
Gooley
Paul R
PR
Parker
Michael W
MW
Batterham
Philip
P
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
D007306:Insecticides; D003634:DDT; D005982:Glutathione Transferase