What's this protein?
N L Y I Q W L K D G G P S S G R P P P S
drumroll ... Trp-Cage!
It's the smallest true protein, with only 20 amino acids, and was derived from the saliva of Gila monsters.
This highly stable mini-protein is important for studies of protein stability, protein folding, and 3D structure.
Even with this small size, it displays secondary structural elements, such as an alpha helix, found in many proteins (image below). There are no known proteins with less than 20 amino acids, and the average size of proteins in humans is around 486 amino acids.