Abstract:

The open reading frame (ORF) of the lectin gene(Ahltn) was cloned from Arisaema heterophyllum Blume and the chief characteristic and structure of the coding protein was analyzed by bioinformatics tools. RNA was extracted from Arisaema heterophyllum Blume, and mRNA was purified and reverse-transcribed into cDNA. The target gene fragments were amplified by PCR and subcloned into pMD19-T vectors, and then transformed into E. coli competent cells. The recombinant plasmids were identified by PCR and further comfirmed by DNA sequencing. Moreover, we analyzed the physicochemical properties, homologous proteins and evolution, secondary structures and three dimensional structures of the AhLTN proteins by using bioinformatics softwares. The Ahltn full length ORF was successfully cloned, which was 561 base pair in length, encoding 186 amino acids. AhLTN was a stable dimer, which was assembled by “C-terminal β-sheet exchange”. Each subunit contained 11 β-sheets, showing a “a triangular prism” type. Three conserved tryptophan located in the center of the three dimensional structure, which constituted the hydrophobic region to keep the stable structure. Bioinformatics analysis showed that AhLTN had the closest relationship to that of Dendrobium catenatum. This paper will provide the basis for the further function study of Ahltn gene and AhLTN protein.

Key words: Arisaema heterophyllum Blume, lectin, gene cloning, bioinformatics analysis