[BioPython] codons and complements

[Jeffrey Chang]

> The IUPAC definitions are at:
>   http://www.chem.qmw.ac.uk/iupac/

As long as we're collecting references to different vocabularies...

NCBI has a reference for IUPAC amino acid definitions:
http://www.ncbi.nlm.nih.gov/collab/FT/aa_abbrevs.html

NCBI has a FASTA format description, where they use '-' for gaps, 'U' for
selenocysteine, 'X' for any amino acid, and '*' for stop codons:
http://www.ncbi.nlm.nih.gov/BLAST/fasta.html

The peptabiol database has a vocabulary for a bunch of non-standard amino
acids (usually found in fungi):
http://www.cryst.bbk.ac.uk/peptaibol
http://sanda.cryst.bbk.ac.uk/peptaibol/nomenclature.html

Using SEC and X for selenocysteine first used in;
Gunzler WA, Steffens GJ, Grossmann A, Kim S-MA,
Otting F, Wendel A, and Flohe L.  (1984)
Hoppe-Seylers Z. Physiol. Chem.  365, 195-212.
(I don't remember where I found this reference)

Jeff