Recombinant binders and their molecular characteristics
| Format . | Size . | Template . | Structure (disulphides?) . | Binding mode . | Characteristic features . |
|---|---|---|---|---|---|
| kD | |||||
| Ig derivative | |||||
| Fab | ∼50 | IgG | Four Ig domains, β-sandwich (yes) | Via six CDR loops, VH/VL interface | Nonrecombinant generation by papain digest of IgG is possible |
| scFv | ∼25 | IgG | Two Ig domains , β-sandwich(yes) | Via six CDR loops, VH/VL interface | A synthetic link stabilizes the noncovalent interaction between VH and VL domains |
| VH | ∼13 | IgG | β-sandwich (yes) | Three VH CDR loops | Single domain antibody; exposed hydrophobic stretch |
| VL | ∼13 | IgG | β-sandwich (yes) | Three VL CDR loops | Single domain antibody; exposed hydrophobic stretch |
| VHH | ∼13 | hcAb | β-sandwich (yes) | Three VHH CDR loops | Small, stable Ig antigen binding unit; recognition of cryptic epitopes |
| V-NAR | ∼9 | Ig-NAR | β-sandwich (yes) | Three V-NAR CDR loops | Small, stable Ig antigen binding unit; recognition of cryptic epitopes |
| Non-Ig binders | |||||
| Monobodies | ∼10 | Fibronectin | β-sandwich (no) | Three CDR-like loops | Ig-like structure lacking disulphides |
| Anticalins | ∼20 | Lipocalin | Goblet-like β-barrel (yes) | Four CDR-like loops | Binding pocket for small molecules and protruding epitopes |
| Affibodies | ∼6.5 | Protein A | Three α-helices (no) | helix-mediated | Bacterial origin, smallest recombinant binder format |
| DARPins | ∼18 | Ankyrin repeat | Helix-turn-helix (no) | planar, flexible surface | Repetitive, modular design |
| Format . | Size . | Template . | Structure (disulphides?) . | Binding mode . | Characteristic features . |
|---|---|---|---|---|---|
| kD | |||||
| Ig derivative | |||||
| Fab | ∼50 | IgG | Four Ig domains, β-sandwich (yes) | Via six CDR loops, VH/VL interface | Nonrecombinant generation by papain digest of IgG is possible |
| scFv | ∼25 | IgG | Two Ig domains , β-sandwich(yes) | Via six CDR loops, VH/VL interface | A synthetic link stabilizes the noncovalent interaction between VH and VL domains |
| VH | ∼13 | IgG | β-sandwich (yes) | Three VH CDR loops | Single domain antibody; exposed hydrophobic stretch |
| VL | ∼13 | IgG | β-sandwich (yes) | Three VL CDR loops | Single domain antibody; exposed hydrophobic stretch |
| VHH | ∼13 | hcAb | β-sandwich (yes) | Three VHH CDR loops | Small, stable Ig antigen binding unit; recognition of cryptic epitopes |
| V-NAR | ∼9 | Ig-NAR | β-sandwich (yes) | Three V-NAR CDR loops | Small, stable Ig antigen binding unit; recognition of cryptic epitopes |
| Non-Ig binders | |||||
| Monobodies | ∼10 | Fibronectin | β-sandwich (no) | Three CDR-like loops | Ig-like structure lacking disulphides |
| Anticalins | ∼20 | Lipocalin | Goblet-like β-barrel (yes) | Four CDR-like loops | Binding pocket for small molecules and protruding epitopes |
| Affibodies | ∼6.5 | Protein A | Three α-helices (no) | helix-mediated | Bacterial origin, smallest recombinant binder format |
| DARPins | ∼18 | Ankyrin repeat | Helix-turn-helix (no) | planar, flexible surface | Repetitive, modular design |