Cloning, Expression and Molecular Characterization of Glutathione Transferase P1-1 Gene from the Camel, Camelus dromedarius

In this study, we report the cloning, expression and characterization of the glutathione transferase isoenzyme P1-1 gene from Camelus dromedarius (CdGSTP1-1). The coding sequence was cloned using RT-PCR. Sequence analysis demonstrated significant differences between amino acid sequence of C. dromedarius and other mammalian GSTP1-1 enzymes. Phylogenetic relationship was studied with different organisms belonging to animal kingdom and revealed that CdGSTP1-1 is grouped with the enzyme from S. scrofa. The 3D homology model of CdGSTP1-1 showed similar fold and topology with the porcine GSTpi enzyme. Gene expression analysis in five camel tissues was examined employing real-time PCR. The highest level of transcripts was found in the camel testis, followed by liver, spleen, kidney and lung. CdGSTP1-1 was heterologously expressed in Eschericia colt BL21(DE3) as a 24 kDa soluble protein and showed to be catalyticly active towards the model substrate 1-chloro-2,4-dinitrobenzene. The results of the present study provide new information into camelid evolution and give further insights into the diversity and complex enzymatic functions of GST superfamily.