Provides text-based searching of records in the Molecular Modeling Database (MMDB), containing 3D macromolecular structures of proteins and polynucleotides; links to the Cn3D structure viewer program (download required). MMDB contains over 28,000 structures and is linked to other NCBI databases including sequences, bibliographic citations, taxonomic classifications, and sequence and structure neighbors.

http://www.ncbi.nlm.nih.gov/sites/entrez?db=structure&otool=umnbmlib