A mu-class glutathione S-transferase from the marine shrimp Litopenaeus vannamei: molecular cloning and active-site structural modeling.
A cDNA clone coding for a mu-class glutathione S-transferase (GST) was isolated from a hepatopancreas cDNA library from the shrimp Litopenaeus vannamei. The deduced amino acid sequence (215 amino acids) has >50% identity to rodents and other mammals mu-class GSTs. Using RT-PCR, the shrimp GST transcript was detected in hepatopancreas, hemocytes, gills, and muscle, but not in pleopods. The shrimp GST sequence was computer modeled and found to fit the classical two-domain GST structure. Domain I, containing the glutathione (GSH) binding site, is more conserved compared to the flexible C-terminal domain II. Residue Q208 appears to be a key to substrate specificity by comparison with mammalian GST mutants. This position is commonly occupied by serine or threonine in mammalian mu-class GSTs, and shrimp Q208 may affect the affinity to substrates like aminochrome or 1,3-dimethyl-2-cyano-1-nitrosoguanidine. This is the first report of molecular cloning and structural modeling of a crustacean GST and provides new insights into the nature of the detoxification response on marine invertebrates.
Contreras-Vergara
Carmen A
CA
Aquatic Molecular Biology Laboratory, Centro de Investigación en Alimentación y Desarrollo, PO Box 1735, Hermosillo Son 83000, México.
Harris-Valle
Citlalli
C
Sotelo-Mundo
Rogerio R
RR
Yepiz-Plascencia
Gloria
G
D000595:Amino Acid Sequence; D000818:Animals; D033202:Anostraca / Q000201:enzymology*; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers; D005982:Glutathione Transferase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D005982:Glutathione Transferase