Molecular cloning and expression analysis of two lectin genes in Sophora flavescens

Plant lectins are greatly introduced in modern medical diagnostics, which play a key role to diagnose the degrees of malignant tumor and used to inhibit different types of cancer cells. To further characterize the structure and function of plant lectins, we cloned, expressed and analyzed two lectin genes from a Chinese medicinal plant Sophora flavescens (sfl1, sfl2). The two genes were successfully cloned by reverse transcription-polymerase chain reaction (RT-PCR). The full-length open reading frame (ORF) of the sfl1 contained 864 bp encoding SFL1 protein with 287 amino acids, whereas the sfl2 contained 891 bp encoding SFL2 protein of 296 amino acids. The two genes were subcloned to pET-22b(+) vector and the recombinant plasmids pET-22b(+)-sfl1 and pET-22b(+)-sfl2 were transformed into E. coli BL21 for protein expression. The two expressed proteins were detected by Western-blotting. The physicochemical properties, homologous proteins and evolution, secondary structures, and three dimensional (3D) structures of the SFL1 and SFL2 proteins were analyzed by bioinformatic tools. Our results provide a foundation for exploring plant lectins as anti-cancer drugs.