Patent ID: 9150849
Filing Date: 2015-10-06
Classification: C12N,C40B

Abstract:
1. A recombinant polypeptide expression library with normalized expression levels of a plurality of expressed polypeptide variants comprising unnatural amino acids, wherein the library is expressed from an expression vector, the library comprising: a) a plurality of expressed target polypeptide variants, wherein at least one of the expressed target polypeptide variants comprises at least one unnatural amino acid residue, and b) a packaging or specificity polypeptide comprising at least one same unnatural amino acid as the at least one expressed target polypeptide variant comprising the at least one unnatural amino acid residue of a), which packaging or specificity polypeptide is essential for viability of the expression vector; wherein expressed polypeptides comprising only natural amino acids are present in the library at a molar ratio of 10:1, or less than 10:1, relative to polypeptides in the library comprising the at least one unnatural amino acid residue of a).