Cloning and expression of the sequence coding ABRaA in Escherichia coli

Abrin is a plant-derived glycoprotein toxin composed of two polypeptide chains, A chain and B chain. The A-chain (molecular weight 30 kDa) as a N-glycosidase is able to catalyzes the deadenylation of the 28S rRNA and thereby inactivate ribosomes. On the other hand, B-chain (molecular weight 35 kDa) is responsible for binding to the target cell and internalization of A-chain. In this study, an abrin A-chain (ABRaA) DNA was isolated from Abrus precatorius by PCR technique and then cloned into a T-vector. This isolated sequence with 753 bp in length was registered to NCBI GenBank with the accession number MF573784, as the first report of A chain abrin DNA. In continue molecular structures and biochemicalcharacteristics of ABRaA were analyzed. The secondary and three dimensional analysis of the polypeptide structure with 28.07 kDa indicated that ABRaA is similar to the RIP-II family of plant proteins. The bacterial expression of ABRaA carried out in BL21 (DE3) strain and subsequently confirmed by Western blot.