The Source Organism browser is a hierarchical representation of all organisms in the NCBI Taxonomy database (Taxonomy).
All organisms which have structures in the PDB are listed as active links in the browser. These organisms are the
source of the individual naturally-occurring polypeptides. The PDB source organism assignment is based on
author/UniProtKB specified mapping of polypeptides.
Here you can browse by source organism, view the number of associated PDB structures, and search for the specific associated structures.