Summary of observed enriching mutations.

Table of HC and LC point mutation, insertion, and deletion events observed during affinity maturation of APE777. The first column indicates the amino acid mutation, listed with Kabat numbering. The second column indicates whether the mutation is in the HC or LC. Columns three and four show the starting and ending nucleotide sequence surrounding the site of mutation, with the mutated nucleotides underlined. Columns five and six indicate the starting and ending nucleotide for point mutations. The last two columns indicate which strategy the mutation was observed in, and at which round it was enriched. Ten of the 11 point mutations were initiated at G or C nucleotides; one of the 11 was initiated at a T. Seven of the point mutations, the deletion, and one of the insertions occurred at known AID hotspots (WRCH, highlighted in bold) located within CDRs 1, 2, or 3. Seven of the 11 point mutations were nucleotide transitions, and four were nucleotide transversions.1Enrichment observed by Sanger sequencing of 40 HC and LC variable regions post-sort round.