Molecular characterization of an α-N-acetylgalactosaminidase from Clonorchis sinensis

Myoung Ro Lee, Won Gi Yoo, Yu Jung Kim, Dae Won Kim, Shin Hyeong Cho, Kwang Yeon Hwang, Jung Won Ju, Won Ja Lee

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The α-N-acetylgalactosaminidase (α-NAGAL) is an exoglycosidase that selectively cleaves terminal α-linked N-acetylgalactosamines from a variety of sugar chains. A complementary DNA (cDNA) clone encoding a novel Clonorchis sinensis α-NAGAL (Cs-α-NAGAL) was identified in the expressed sequence tags database of the adult C. sinensis liver fluke. The complete coding sequence was 1,308 bp long and encoded a 436-residue protein. The selected glycosidase was manually curated as α-NAGAL (EC based on a composite bioinformatics analysis including a search for orthologues, comparative structure modeling, and the generation of a phylogenetic tree. One orthologue of Cs-α-NAGAL was the Rattus norvegicus α-NAGAL (accession number: NP-001012120) that does not exist in C. sinensis. Cs-α-NAGAL belongs to the GH27 family and the GH-D clan. A phylogenetic analysis revealed that the GH27 family of Cs-α-NAGAL was distinct from GH31 and GH36 within the GH-D clan. The putative 3D structure of Cs-α-NAGAL was built using SWISS-MODEL with a Gallus gallus α-NAGAL template (PDB code 1ktb chain A); this model demonstrated the superimposition of a TIM barrel fold (α/β) structure and substrate binding pocket. Cs-α-NAGAL transcripts were detected in the adult worm and egg cDNA libraries of C. sinensis but not in the metacercaria. Recombinant Cs-α-NAGAL (rCs-α-NAGAL) was expressed in Escherichia coli, and the purified rCs-α-NAGAL was recognized specifically by the C. sinensis-infected human sera. This is the first report of an α-NAGAL protein in the Trematode class, suggesting that it is a potential diagnostic or vaccine candidate with strong antigenicity.

Original languageEnglish
Pages (from-to)2149-2156
Number of pages8
JournalParasitology Research
Issue number5
Publication statusPublished - 2012 Nov

ASJC Scopus subject areas

  • Parasitology
  • veterinary(all)
  • Insect Science
  • Infectious Diseases


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