title: Molecular characterization of an insecticide-induced novel glutathione transferase in silkworm.
abstract: BACKGROUND
  The glutathione transferase (GST) superfamily is involved in the detoxification of various xenobiotics. We have identified a GST mRNA that was induced in the fat bodies of a silkworm strain exhibiting diazinon resistance and have investigated the enzyme properties of this GST.
  
  
  METHODS
  A soluble recombinant protein was overexpressed in Escherichia coli. Amino acid residues of interest were changed to alanine by site-directed mutagenesis.
  
  
  CONCLUSIONS
  Phylogenetic analysis of the deduced amino acid sequence indicates that this GST belongs to an unclassified group previously reported in mosquitoes. This enzyme, named bmGSTu, has highly conserved amino acid residues, including Tyr7, Ser12 and Asn50. A recombinant bmGSTu was able to catalyze the biotranslation of glutathione with 1-chloro-2,4-dinitrobenzene, a synthetic substrate of GST. Kinetic analysis of bmGSTu mutants indicated that Tyr7, Ser12 and Asn50 are involved in enzyme function.
  
  
  CONCLUSIONS
  These results support the hypothesis that bmGSTu may play a role in insecticide resistance in Bombyx mori.
authors.affiliation: Faculty of Agriculture, Kyushu University Graduate School, Higashi-ku, Fukuoka, Japan. yamamok@agr.kyushu-u.ac.jp
authors.forename: Kohji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ichinose
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Aso
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Banno
authors.forename: Makoto
authors.initials: M
authors.lastname: Kimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakashima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D007306:Insecticides; D011994:Recombinant Proteins; D005982:Glutathione Transferase