ProteinData Source Information
ProteinData is based on a wide range of sources, with enhancement at the Wolfram Research Companies by both human and algorithmic processing. ProteinData is continually maintained with the latest available information, with automatic updating when ProteinData is used inside Mathematica.
Among current principal sources for ProteinData are:
Berman, H. M. et al. "The Protein Data Bank." Nucleic Acids Research, 28, no. 1, (2000): 235-242. »
United States National Center for Biotechnology Information. "Entrez Protein." 2009. »
UniProt Consortium. "UniProt." 2009. »