Characterization and phylogenetic analysis of a mitochondrial targeting alpha/beta hydrolase protein in Strongyloides ratti

Strongyloides ratti is widely used as an experimental model for studying and diagnosing humans strongyloidiasis. The alpha/beta hydrolase domain proteins are ubiquitously distributed across all organisms. In this study, a ۷۸۰-nucleotide cDNA fragment was amplified by RT-PCR, and BLAST analysis revealed that ۹۸.۵۴% sequence identity with the only incomplete S. ratti mRNA sequence available in GenBank (XM_۰۲۴۶۵۲۳۹۴.۱). Using this fragment as a probe, two expressed sequence tags (ESTs), ۸۵۶ bp (FC۸۱۵۹۱۰.۱) and ۵۲۶ bp (BI۷۴۲۴۹۸.۱), corresponding to the ۳'and ۵' ends, respectively, were identified and assembled into a full length cDNA of ۹۱۹ bp, designated SrABH. Its amino acid sequence exhibited ۹۷.۹۸% identity with the only available S. ratti sequence in GenBank (XP_۰۲۴۵۰۵۹۷۵.۱). The molecular weight (MW) and isoelectric point (pI) of the protein are ۳۳.۴۸۴ kDa and ۷.۱۸, respectively. Signal peptide analysis indicated the absence of a secretion signal, however a mitochondrial targeting cleavage site was identified between amino acids ۲۱-۲۲. The highly conserved motif consists of nine amino acids spanning positions ۱۱۱ to ۱۲۰. The ۳D structural analysis revealed that SrABH consists of ۹ alpha-helices (۳۹.۱۸%), ۸ beta-sheets (۱۸.۲۱%), and loop regions  (۴۲.۶۱%). Phylogenetic analysis clustered SrABH with related nematode sequences, displaying by a high bootstrap support of ۹۸. The lowest genetic distance (۰.۰۱%) was observed between SrABH and the only sequence isolated from S. ratti (XP_۰۲۴۵۰۵۹۷۵.۱). Given its molecular characteristics, this parasite’s data may be valuable in structure-based drug design strategies using S. ratti as a model system for the human pathogen S. stercoralis.

کلیدواژه ها:

Esterase ، alpha/beta hydrolase domain ، Strongyloides ratti ، RT-PCR ، mitochondria