Certain bovine antibodies have ultra-long long complementarity-determining regions (CDRs) that contain a knob for antigen interaction, which is connected to the antibody through a stalk. Here, the authors combine biophysical experiments and MD simulations and show that the stalk length is critical for the folding and stability of these antibodies. The authors also demonstrate that ultra-long bovine CDRs can be grafted into human antibodies, and furthermore show that de novo designed mini-domains that bind to the SARS-CoV-2 spike protein with high affinity can be integrated as a knob in ultra-long CDRs in bovine and human antibodies, which neutralize SARS-CoV-2.
- Hristo L. Svilenov
- Julia Sacherl
- Johannes Buchner
