cDNA - Protein fusions: Covalent protein-gene conjugates for the in vitro selection of peptides and proteins

We report a method for the synthesis of covalent cDNA-protein fusions for p rotein display applications. A branched mRNA template was developed which c arries a peptidyl acceptor and a reverse transcription primer at the 3'-end . Translation in vitro followed by reverse transcription produced a protein covalently bonded to its encoding cDNA. Both single- and double-stranded c DNA -protein fusions were prepared. cDNA -protein fusions are stable in alk ali and resistant to ribonucleases. Their simple preparation and their resi stance towards degradation should make cDNA - protein fusions a useful tool for the in vitro selection and evolution of high affinity ligands from lar ge libraries of polypeptides.