Glycine

Glycine Gly(G)

Glycine (G) is sometimes grouped with the hydrophobic amino acids; however, Glycine is unique in having no side chain. This lack of a side chain allows Glycine to accept bond angles (backbone turns) that are far more extreme than other amino acids. It therefore plays a key role in allowing a wide range of conformations in proteins without undue strain.

Glycine is rarely found in an alpha helix, as it tends to bend too freely and therefore it deforms the helix. It is commonly found in u-turns.

Notes

• Glycine's flexibility allows a player to use the tactic known as the Glycine Hinge.

• Because of this flexibility, it may be advantageous to select a section of loop including the nearest glycine when performing either a rotate or a normalize Tweak. The glycine will be more likely or willing to bend than the others and therefore the tweak will be more successful.

• A low-scoring amino acid right next to a glycine can often be helped as follows: Lock the two amino acids on either side of this pair. Then local wiggle. If the other amino acid owes its low score to being bent in a conformation it does not like, then the local wiggle will transfer some of this bend to the glycine, which will often accept it. This will result in an increased score.

More information can be found at http://en.wikipedia.org/wiki/Glycine