Stoker N G, Grant K A, Dockrell H M, Howard C R, Jouy N F, McAdam K P
Department of Clinical Sciences, London School of Hygiene and Tropical Medicine, U.K.
Gene. 1989 May 15;78(1):93-99. doi: 10.1016/0378-1119(89)90317-x.
Plasmid cloning vectors have been constructed which allow genes originally cloned in lambda gt11 to be expressed at a high level in Escherichia coli. They are based on the pEMBL and pUC vectors, with the genes transcribed from the lac promoter. The EcoRI site in the vector has been altered to be in the same reading frame as the site used for cloning in lambda gt11. Cloned proteins are expressed fused to a 2-kDa leader sequence containing a run of six Aparagine residues which considerably improves the stability of the recombinant proteins, but does not interfere with immunological assays. Using these vectors, the Mycobacterium leprae 18-kDa protein was expressed at 20 mg per litre of culture and constituted 15% of total cell protein.
