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. 2002 Jun;106(2):237–245. doi: 10.1046/j.1365-2567.2002.01413.x

Figure 1.

Figure 1

Construction of N- and C-terminal fusion proteins between the B-chain of human insulin (InsB) and the B-subunit of cholera toxin (CTB). (a) The expression plasmid pAFtac1 was used to construct plasmids carrying the gene fusions containing CTB and InsB. The different CTB genes were inserted between NheI and HindIII sites in the vector, allowing the insertion of in-frame InsB sequences, as indicated. (b) The sequences of the linkers in the plasmids pHS-IC and pHS-CI in which the InsB sequence was linked to the 3′ and 5′ end of the CTB gene, respectively. In pHS-IC the InsB sequence was placed between NheI and SspI sites with additional synthetic sequence replacing the CTB gene lost by digestion. As threonine was the final residue of the InsB protein and also the first residue of mature CTB, this residue was not repeated. In pHS-CI the sequence was inserted between HpaI and HindIII sites. Asterisks denote translation stop signals. (c) The DNA sequence of the InsB gene. The G residue underlined in bold was changed to T in pHS-CI(m), resulting in a change from alanine to serine at position 14.