Design of affinity maturation libraries.

Two affinity maturation libraries were designed based on binding data of variants of ADAPTERBB2-1, which showed that T7, Y10, H11 and Y38 were important for ERBB2-binding. These four residues were preserved in a conservative design (library 1) that only diversified the remaining seven positions using the degenerate codon NNK. A semi-conservative design (library 2) included 50% of conservation at the four positions that were preserved in library 1 as well as at position 39; the remaining 50% was diversified using NNK.