Fig. 6: Principles of structural and stability convergence in antibodies with ulCDRs.
From: Stability convergence in natural antibodies with ultra-long hypervariable loops
There is a structural consensus between a Fab scaffold and different ulCDRs. The conserved LC contributes to stability. While the stalk base maintains important stabilizing interactions, the antigen-binding properties of the swapped knob are preserved. Depicted is the crystal structure of NC-Cow1 wt Fab (PDB:6OO0), where the ulCDR is shown as a blue stalk and a red knob, the rest of the Fd region in green, and the LC in pink.
