Characterization and localization of Opisthorchis viverrini fructose-1,6-bisphosphate aldolase

•OvFBPA-1 was classified based on highly conserved active residues to class-I FBPA.•Other two isoforms of OvFBPAs were identified by sequence analysis.•OvFBPA-1 antibody was able to detect native OvFBPA-1 in Ov ES products.•OvFBPA-1 protein was mainly distributed in the parenchyma cell of Ov.

Opisthorchis viverrini (Ov) infection is a long-time public health problem in Thailand that can lead to bile duct cancer, cholangiocarcinoma (CCA). Characterization of the Ov proteins at a molecular level will increase our knowledge of host-parasite interaction that can be applied to new drug, vaccine, or immunodiagnostic development. In this study, an important enzyme in the Ov glycolytic pathway, fructose-1,6-bisphosphate aldolase (FBPA), that had been obtained from a previous study was characterized and immunolocalized. The full-length sequence of OvFBPA gene is 1089 bp and encodes 362 amino acids with a predicted molecular weight and isoelectric point of 39.54 kDa and 7.61, respectively. Additionally, three OvFBPA isoforms were identified by sequence analysis. The amino acid sequence of OvFBPA-1 characterized in this study shared 98% identity to FBPA isoform 1 of Clonorchis sinensis that was classified based on highly conserved active residues to class-I FBPA. The recombinant OvFBPA-1 protein was expressed as a soluble form in Escherichia coli at 25 °C with N-terminal His-tagged fusion protein and the purified OvFBPA-1 protein was used to generate polyclonal antibody in mice. Antibody against rOvFBPA-1 protein was able to detect the native OvFBPA-1 protein in both Ov infected hamster liver section and Ov excretory-secretory (ES) products by immunohistochemistry and western blotting, respectively.

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