Team:NTHU Formosa/Nanobody
Nanobody
Nanobodies are single variable domain antibody fragments (VHH) derived from heavy-chain only antibodies discovered and identified in at least two types of organisms, camelidae (e.g., camel and llama) and cartilaginous fish (e.g., nurse shark and Wobbegong).
The molecular size of nanobody is about 3 nm (15kDa), 1/10000 of hair diameter. Such property earned it the name, nanobody. They are more hydrophilic than conventional antibodies. They withstand big pH variation. Their small size gives them the ability to penetrate the tissue faster and to reach deeper into the binding pockets of enzymes. Being able to refold after heat denaturation keeps nanobodies functional and active at 70°C or 2-hour 90°C heat shock.
Nanobodies retain full antigen binding capacity and are considerably stable. Conventional antibodies are composed with variable domains along with heavy chains and light chains. When binding with proteins, all three parts of them are necessarily involved. Hence, nanobodies’ comparably simple structure greatly increases their antigen binding affinity. What’s even better is that it’s less costly to make nanobodies than antibodies.
Compared with antibodies, the unique features that nanobodies possess make them ideal for therapeutic and bioengineering tools. As a result, nanobodies are applied in our mechanism.
| Name | Conventional antibody | Nanobody |
|---|---|---|
| Size | 150–160 kDa | 12-15 kDa |
| Composition | Variable domains + heavy chains + light chains | Variable domain fragments |
| Structure(in comparison) | Complex | Simple |
| Antigen binding affinity | High | Even better(nano- to- picomolar affinities) |
| Thermal Stability | 65°C for 20 mins diminishes the activities of almost all antibodies | Highly heat-resistant (functional and active at 70°C or even at 2-hour 90°C heat shock) |
| Price | Varies with the products | Less expensive than antibodies |