Nanobody

Protein Data Bank ID: 1MEL
Protein Name: Nanobody
Organism: Camelus dromedarius
Title of Drawing: “Bedouin Riding a Camel“

It is not only the drawing showing a dromedary, but also the inspiring protein originates from a dromedary camel.

This small protein is called nanobody. Sounds cool, but what is a nanobody? It is a fragment of an antibody, in this case, an antibody from a camel. Antibodies serve our immune system, they can bind pathogenic substances and protect our body from dangerous invaders. Antibodies are widely used in medicine and biology, e.g. for passive immunization or targeting of substances (mostly proteins) of interest. In both fields nanobodies have their advantages. They are stabler and much smaller than conventional antibodies and can pass narrow holes. So literally, for this nanobody camel it is easy to go through the eye of a needle.

In the following illustration you can see how small the nanobody (right) is compared to the conventional antibody (left) and to the camel antibody (middle). The antigen binding regions (variable domains) are shown in yellow and green. The nanobody corresponds to the variable domain of the camel antibody.

Image source: http://www.structuralbiology.be/chaperones.