Abstract
Bovines have evolved a subset of antibodies with ultra-long heavy chain complementarity determining regions that harbour cysteine-rich knob domains. To produce high-affinity peptides, we previously isolated autonomous 3-6 kDa knob domains from bovine antibodies. Here, we show that binding of four knob domain peptides elicits a range of effects on the clinically validated drug target complement C5. Allosteric mechanisms predominated, with one peptide selectively inhibiting C5 cleavage by the alternative pathway C5 convertase, revealing a targetable mechanistic difference between the classical and alternative pathway C5 convertases. Taking a hybrid biophysical approach, we present C5-knob domain co-crystal structures and, by solution methods, observed allosteric effects propagating >50 Å from the binding sites. This study expands the therapeutic scope of C5, presents new inhibitors, and introduces knob domains as new, low molecular weight antibody fragments, with therapeutic potential.
| Original language | English |
|---|---|
| Article number | e63586 |
| Number of pages | 27 |
| Journal | eLife |
| Volume | 10 |
| Early online date | 11 Feb 2021 |
| DOIs | |
| Publication status | Published - 18 Mar 2021 |
Bibliographical note
Publisher Copyright:© 2021, Macpherson et al.
Keywords
- Allosteric Regulation/drug effects
- Animals
- Cattle
- Complement C5/antagonists & inhibitors
- Drug Discovery
- Molecular Docking Simulation
- Peptides/chemistry
- Protein Conformation/drug effects