PERMUTEINS OF INTERLEUKIN-1-BETA - A SIMPLIFIED APPROACH FOR THE CONSTRUCTION OF PERMUTATED PROTEINS HAVING NEW TERMINI

A technique for the rapid and simple generation of permutated versions of the interleukin-1-beta (IL-1-beta) gene is described. In this method, the human IL-1-beta cDNA is twice amplified by the polymerase chain reaction (PCR) and the resulting DNA fragments are ligated in tandem. Between the two genes, the DNA sequence encodes a short four amino acid loop to link the native N- and C-terminal ends of the IL-1-beta protein. By using PCR amplification from this starting template, a new version of the IL-1-beta cDNA was obtained that encodes a permutated form of the IL-1-beta protein where the new N- and C-terminal amino acids correspond to residues 65 and 64 of the native IL-1-beta sequence, respectively. The name 'permutein' is proposed to describe proteins generated by this technology. The molecular profile (IL-1 receptor binding, biologic activity and solution properties) of the IL-1 permutein produced by this technology, permutein 65/64, is shown to be identical to that of native IL-1-beta. The approach should be useful to define further the structural features of this protein that are important for its function.