Glutathione transferases (GSTs; EC. 2.5.1.18) are a large family of multifunctional enzymes that play crucial roles in the metabolism and inactivation of a broad range of xenobiotic compounds. In the present work, we report the kinetic and structural characterization of the isoenzyme GSTM1-1 from Camelus dromedarius (CdGSTM1-1). The CdGSΤM1-1 was expressed in E. coli BL21 (DE3) and was purified by affinity chromatography. Kinetics analysis showed that the enzyme displays a relative narrow substrate specificity and restricted ability to bind xenobiotic compounds. The crystal structures of CdGSΤM1-1 were determined by X-ray crystallography in complex with the substrate (GSH) or the reaction product (S-p-nitrobenzyl-GSH), providing snapshots of the induced-fit catalytic mechanism. The thermodynamic stability of CdGSTM1-1 was investigated using differential scanning fluorimetry (DSF) in the absence and in presence of GSH and S-p-nitrobenzyl-GSH and revealed that the enzyme’s structure is significantly stabilized by its ligands. The results of the present study advance the understanding of camelid GST detoxification mechanisms and their contribution to abiotic stress adaptation in harsh desert conditions.
Dromedary camels or, more specifically, one-humped camels (Camelus dromedarius), are described as having a high productive potential, and for centuries, they have been used by people (namely nomads) in arid and hot regions as multipurpose animals for physical labor, transport, the production of milk, meat, wool, hair, and skin, and for racing and tourism [...]
Considering the importance of maintaining the genetic diversity in native animals, this study conducted to analyse genetic diversity in dromedary populations in the north of Kerman province, Iran, using eight autosomal microsatellite markers. Eighty-one blood samples were collected from five different populations and DNA was extracted. The highest and the lowest allele number and effective alleles were shown in YWLL08 (21 and 4) and VOLP32 (14.97 and 3.11), respectively. The expected heterozygosity varied from 0.778 in Sahra-e Jahad population to 0.847 in Nogh population. The test for Hardy-Weinberg equilibrium showed significant deviations in most loci. The mean multilocus FST value (0.057) suggested that differentiation is moderate between populations. From total genetic diversity, only 6% were due to differentiation among populations, while the remaining 94% corresponded to differences among individuals within each population. The results of the current study indicated that the Camelus dromedarius populations in the north of Kerman province have a relativity high genetic variation and the data could be useful for designing the breeding strategies and conservation. The degree of variability demonstrated implies that studied populations are rich reservoirs of genetic diversity that must be preserved. A future direction to our study can be studying all of the Iranian Camelus dromedarius populations to better evaluate the level of inbreeding and establish the appropriate conservation strategies aimed to avoid losses of genetic diversity.
Structural and Functional Characterization of Camelus dromedarius Glutathione Transferase M1-1
