Foldit's version of Tyrosine
Tyrosine (TYR Y) is one of the more hydrophobic amino acids. Its shape on Foldit is similar to that of phenylalanine, but it has a "stick" on top.
Tyrosine / TYR / Y
In the Foldit Lua interface, the functions structure.GetAminoAcid and structure.SetAminoAcid use lowercase "y" for tyrosine.
More information can be found at http://en.wikipedia.org/wiki/Tyrosine