title: Similarity of a 16.5kDa tegumental protein of the human liver fluke Opisthorchis viverrini to nematode cytoplasmic motility protein.
abstract: Opisthorchis viverrini is the causative agent of human opisthorchiasis in Thailand and long lasting infection with the parasite has been correlated with the development of cholangiocarcinoma. In this work we have molecularly characterized the first member of a protein family carrying two DM9 repeats in this parasite (OvDM9-1). InterPro and other protein family databases describe the DM9 repeat as a protein domain of unknown function that has been first noted in Drosophila melanogaster. Two paralogous proteins have been partially characterized in the genus Fasciola, Fasciola hepatica TP16.5, a novel tegumental antigen in human fascioliasis and, recently F. gigantica DM9-1, a parenchymal protein with structural similarity to nematode cytoplasmic motility protein (MFP2). In this study, we show further evidence that this family of trematode proteins is related to MFP2 in sequence and structure. Soluble recombinant OvDM9-1 was used for structural analyses and for production of specific antisera. The native protein was detected in soluble and insoluble crude worm extracts and in seemingly various oligomeric forms in the latter. The potential for oligomerization was supported by cross-linking experiments of recombinant OvDM9-1. Structure prediction suggested a β-rich secondary structure of the protein and this was supported by a circular dichroism analysis. Molecular modeling in Phyre2 identified both MFP2 domains as distant homologs of OvDM9-1. The protein was located in tegumental type tissue and the cecal epithelium in the mature parasite. Recombinant OvDM9-1 was used as target in indirect ELISA but sera from infected hamsters showed only marginal reactivity towards it. It is proposed that OvDM9-1 and other members of this protein family have a role in cellular transport through functions on the cytoskeleton.
authors.affiliation: Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12121, Thailand.
authors.forename: Nipawan
authors.initials: N
authors.lastname: Labbunruang
authors.affiliation: Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12121, Thailand.
authors.forename: Wansika
authors.initials: W
authors.lastname: Phadungsil
authors.affiliation: Food-borne Parasite Research Group, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Smarn
authors.initials: S
authors.lastname: Tesana
authors.affiliation: School of Science, RMIT University, Bundoora, Victoria 3083, Australia.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Smooker
authors.affiliation: Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12121, Thailand. Electronic address: rgrams@tu.ac.th.
authors.forename: Rudi
authors.initials: R
authors.lastname: Grams
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D006224:Cricetinae; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009889:Opisthorchiasis / Q000469:parasitology*; D009891:Opisthorchis / Q000235:genetics / Q000378:metabolism*; D009928:Organ Specificity; D011487:Protein Conformation; D017422:Sequence Analysis, DNA
chemical_list: D015801:Helminth Proteins; D020409:Molecular Motor Proteins
keywords: Ascaris suum; Cytosolic motility protein; DM9 repeat; Foodborne trematodiasis; Opisthorchis viverrini