Expression and purification of MERS-CoV envelope protein, an essential viroporin, using the baculovirus expression system

Background and Objectives: The causative agent of Middle East Respiratory Syndrome (MERS) is a zoonotic Coronavirus (MERS-CoV) identified in Saudi Arabia in 2012. The envelope (E) protein of MERS-CoV is a small viral protein which plays several essential roles during virus replication. To facilitate study of the structure and function of the E protein, recombinant MERS-CoV E protein was expressed using the baculovirus expression system.Materials and Methods: A recombinant E open reading frame including an 8-histidine tag at the amino terminus was de-signed and cloned into a baculovirus transfer vector. Following construction of a recombinant virus insect cells were infected and the expression of the E protein assessed by SDS-PAGE and Western blotting.Results: Recombinant E protein, tagged at the N-terminus with a polyhistidine sequence, with a molecular mass of 10.18 kD was identified by Western blotting with an anti-His antibody. Following large scale infection E protein was released by detergent mediated lysis of infected cells and purified by Immobilized Metal Ion Affinity Chromatography (IMAC).Conclusion: Purified full length recombinant MERS-CoV E protein can be isolated by IMAC and is suitable for further functional, biophysical or immunological studies.