Abstract：A new cDNA, named Dd-ace-1, encoding an acetylcholinesterase (AChE, EC3.1.1.7) was isolated from the sweet potato stem nematode, Ditylenchus destructor. The full-length cDNA, carrying the trans-spliced SL1 lea- der sequence, is 2517bp long with an open reading frame of 836bp encoding 611 amino acid residues (GenBank a- cession no. EF583057). The complete amino acid sequence of AChE deduced from the cDNA consists of 21 resi- dues for the putative signal peptide and possesses a potential cleavage-addition site(ω) for a glycophosphatidylin- ositol anchor(GPI) at position 583 and 562 residues for the mature protein with a predicted molecular weight of 70144.12D. The conserved motifs involved in the catalytic triad, the choline binding sit and 11 aromatic residues lining the catalytic gorge were present in the Dd-ACE-1 deduced protein. The prediected protein shared with str- ong homology with Caenorhabditis elegans ACE-3 and C. elegans ACE-4. Phylogenetic analysis based on other nematodes and species AChEs showed that the deduced AChE formed a cluster with ACE-3s.
