Molecular characterization and tissue distribution of Fatty Acid Binding Protein (FABP) encoding gene in Schistosoma mekongi

Abstract

The cDNA encoding SmekFABP of adult Schistosoma mekongi was cloned and sequenced. The nucleotide sequence of SmekFABP was 582 bp in length. The nucleotide sequence of SmekFABP showed an open reading frame encoding FABP containing 132 amino acids. The SmekFABP amino acid sequences showed the highest degree of identity with the S. japonicum (GenBank: AAA64426) at 95.4%. The identity of SmekFABP amino acid sequences with other schistosome species (S. mansoni, and S. haematobium showed at 91.7 and 90.2% respectively. The expected molecular weight of rSmekFABP determined from its constituent amino acids is 14.82 kDa and the predicted molecular weight of rSmekFABP protein with histidine tag is 15.5 kDa. In this study we got one major band at 26 kDa, that could be rSmekFABP that form a complex protein, and the faint band that was 15.5 kDa, which is possible to be the rSmekFABP. A high degree of similarity and identity of S. mekongi with S. japonicum FABP in both nucleic and amino acid, and similarity in localization of worm tissue, indicates that they share a common ancestor. The low degree of conservation observed from amino acid sequences of mammalian hosts could reveal its applicable for using as the vaccine candidate against the schistosome infection which may not interfere with the hosts’ FABP molecule during the vaccination. One immunogenic epitope was predicted by five programs (Hopp & Woods; Welling, Parker, B-EpiPred and ABCpred), it was 87-DSESKITQTQKDAKN-101. Base on bioinformatics approach, this region of amino acid sequence could possible to be a vaccine candidate that have dual protection against infection of both S. mekongi and Fasciola spp., and it could have a potential to be CTL and Major Histocompatibility Complex-I (MHC-I) epitope.

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