Molecular Conformation And Anti-tumor Activity Of Truncated Cell Toxin, Gelonin

Gelonin, a protein toxin derived from seeds of the plant Gelonium. multiflorum, consists of 251 amino acids with the molecular weight of 28 000. It is a specific RNA N-glycosidase which catalyzes the hydrolysis of N-glycosidic bond of A₄₃₂₄ in the 28S ribosomal RNA from 60S subunits of eukaryotic ribosome, leading to cell death by inhibiting protein synthesis. In addition, Gelonin also has DNase-like and glycosylase activity to degrade chromosomal and nucleus DNA. Gelonin, as type-I ribosome inactivating proteins (RIPs), is less toxic to intact eukaryotic cells than that of type- II RIPs because of lacking B chain, a cell surface binding domain. Therefore, type-I RIPs has being used as agents to study and treat autoimmune disease and malignant tumor.An open reading frame (ORF) of gelonin gene was inversely deduced from the amino acid sequence. Based on the favorable code of protein synthesis in E.coli and the requirement of gene cloning in the subsequent work, the chemical synthesis of the ORF was designed as follows: four fragments from the length of 175 bp to 220 bp were divided and the single-strand fragments with the length of 100 to 120 nucleotides in two complementary strands were chemically synthesized. Then, the two...