摘要 |
The present invention relates to a method for preparing positive polypeptide variants by shuffling different nucleotide sequences of homologous DNA sequences by in vivo recombination comprising the steps of (a) forming at least one circular plasmid comprising a DNA sequence encoding a polypeptide, (b) opening said circular plasmid(s) within the DNA sequence(s) encoding the polypeptide(s), (c) preparing at least one DNA fragment comprising a DNA sequence homologous to at least a part of the polypeptide coding region on at least one of the circular plasmid(s), (d) introducing at least one of said opened plasmid(s), together with at least one of said homologous DNA fragment(s) covering full-length DNA sequences encoding said polypeptide(s) or parts thereof, into a recombination host cell, (e) cultivating said recombination host cell, and (f) screening for positive polypeptide variants.
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