| 20100216191 | Method for Manufacturing a Modified Peptide - The present invention relates to a method for manufacturing a modified polypeptide from a first polypeptide, said modified polypeptide exhibiting altered binding properties to a target molecule and/or having a different amino acid sequence compared to a first polypeptide comprising the steps of a) providing a first cell comprising a nucleic acid molecule encoding for a first fusion polypeptide, said first fusion polypeptide comprising at least one first polypeptide and a transcriptional activation domain, and comprising optionally a nucleic acid molecule encoding for a second fusion polypeptide, said second fusion polypeptide comprising the target molecule or a polypeptide domain binding the target molecule and a DNA binding domain, whereby the cell further comprises a reporter gene encoding a reporter polypeptide operably linked to an upstream transcriptional regulatory sequence comprising a DNA binding site as target for the at least one first polypeptide or optionally a DNA binding site for the DNA binding domain of the second fusion polypeptide, b) cultivating the cells of step a), c) identifying at least one cell expressing the reporter polypeptide, d) isolating at least one nucleic acid molecule encoding for at least one first polypeptide of the at least one cell identified in step c), e) modifying the at least one nucleic acid molecule of step d) by introducing at least one mutation thus obtaining at least one modified nucleic acid molecule encoding for at least one modified polypeptide, f) introducing the at least one modified nucleic acid molecule of step e) into at least one second cell comprising optionally a nucleic acid molecule encoding for a second fusion polypeptide, said second fusion polypeptide comprising the target molecule or a polypeptide domain binding the target molecule and a DNA binding domain, and g) repeating steps a) to f) at least twice until a nucleic acid molecule encoding for a modified polypeptide is obtained and isolated in step d) exhibiting predetermined altered binding properties to the target molecule compared to the at least one first polypeptide and/or having a different amino acid sequence compared to the first polypeptide, wherein in the repeating steps a) to d) the first polypeptide is exchanged with the modified polypeptide of step e). | 08-26-2010 |
