Identification, characterization and structure of a new Delta class glutathione transferase isoenzyme

Abstract

The insect GST (glutathione transferase) supergene family encodes a varied group of proteins belonging to at least six individual classes. Interest in insect GSTs has focused on their role in conferring insecticide resistance. Previously from the mosquito malaria vector Anopheles dirus, two genes encoding five Delta class GSTs have been characterized for structural as well as enzyme activities. We have obtained a new Delta class GST gene and isoenzyme from A. dirus, which we name adGSTD5-5. The adGSTD5-5 isoenzyme was identified and was only detectably expressed in A. dirus adult females. A putative promoter analysis suggests that this GST has an involvement in oogenesis. The enzyme displayed little activity for classical GST substrates, although it possessed the greatest activity for DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane] observed for Delta GSTs. However, GST activity was inhibited or enhanced in the presence of various fatty acids, suggesting that the enzyme may be modulated by fatty acids. We obtained a crystal structure for adGSTD5-5 and compared it with other Delta GSTs, which showed that adGSTD5-5 possesses an elongated and more polar active-site topology.

Computational Methods in Drug Discovery

“…For example, structure-based methods successfully predicted the metabolism of celecoxib and its 13 analogs through CYP2C9 (Ahlstrom et al, 2007a,b). In addition to some P450 isoforms, X-ray structures of the ligand-binding domain of prenane X receptor (Xue et al, 2007), the transcription regulator of CYP3A4 (Yano et al, 2004), glutathione S-transferases (Udomsinprasert et al, 2005), and drug transporters such as Pglycoprotein (Aller et al, 2009) have been determined. Structural information about prenane X receptor and drug transporters can be used to predict drug-drug interactions through the induction of CYP3A4 or transport channels.…”

Recognition and Detoxification of the Insecticide DDT by Drosophila melanogaster Glutathione S-Transferase D1

“…4 GSH-dependent DDTase activity was first discovered in Musca domestica (housefly), 5 and it was then shown that purified housefly proteins with DDTase activity also had biochemical activities typical of GSTs. 6 Since then, GSTs from Drosophila melanogaster, 7 Anopheles gambiae, 2 Anopheles dirus, 8 and Aedes aegypti 9 have been cloned and shown to have DDTase activity. Despite the discovery that there are many GSTs with DDTase activity, the details of how DDT binds into the active site of a GST are still lacking.…”

Crystallization and preliminary X-ray crystallographic studies of the ρ-class glutathioneS-transferase from the Antarctic clamLaternula elliptica

“…The data-collection statistics are summarized in Table 1. The coordinates of other class GSTs [-class GST from Anopheles dirus (PDB code 1r5a; Udomsinprasert et al, 2005) and -class GST from Arabidopsis thaliana (PDB code 1f6b; Huang et al, 2001)] were used as a search model to solve the phase problem by molecular replacement (MR) using the program CNS (Brü nger et al, 1998). All attempts to solve the structure by the MR method were unsuccessful.…”