Figure 2.

Protein sequences of nanobodies’ framework. The Yan, Wang, Wei, and Ju libraries used cAbBCII10 and its humanized version (h-NbBCII10_FGLA). Amino acids with red color indicate humanized positions. The NaLi-H1 library used sdAb^D10 humanized version (hs2dAb). Amino acids with red color indicate humanized positions. The McMahon library used a consensus framework derived from llama genes IGHV1S1-S5. The Zimmermann library used three scaffold sequences corresponding to three different CDR3 lengths. The three sequences from top to bottom represent three groups—concave (six amino acids for CDR3), loop (12 amino acids for CDR3), and convex (16 amino acids for CDR3). Amino acids with red color indicate the non-conserved residues among these three scaffolds.