Using Front Door #2:
Link from P53 Tumor Suppressor Protein Sequence Records to Structure Record

Front Door #2 Search the Entrez Protein database and then "Display" the associated Structure records. Note: Any protein sequence that was extracted from a 3-D structure record will have a "Structure" option in its "Links" menu. Rather than opening the Links menu of each protein sequence in your search results, a quick way to find all the associated structure records is to use the "Structure Links" option in the "Display" menu near the top of the search results page. Example:  Search Entrez Protein for: P53 Tumor Suppressor Select "Structure Links" from the "Display" menu near the top of the search results page.

search the Entrez Protein database for:   P53 Tumor Suppressor   the document summary ("docsum") page gives brief title listings for the records your retrieved. The last line of each listing is the "FASTA-formatted sequence identifier". It includes: the GI number of the protein sequence the source database, indicating to which subset of Entrez Proteins the record belongs(e.g., "gb" for GenBank translation; "ref" for refseq"; "pdb" for "Protein Data Bank"; etc.) the accession number of the record from which the sequence was extracted if the protein sequence is from a structure record that contains multiple protein chains (e.g., A, B, C), the protein chain will be indicated after the accession number. (E.g., The 1TUP structure is made from 3 protein chains: A, B, and C. The sequence of each chain was extracted into its own protein record. All three protein records point back to the same 3-D structure: 1TUP.) the presence of the letters "pdb" in the FASTA-formatted sequence identifier are the clue to knowing that these sequence records have an associated, resolved structure follow the "Structure" option in the "Links" menu for any one of the three structures to view the corresponding structure record. (Note: The Links menu also contains an option for "3D Domains". Those are derived from components of structure records. More information about 3D Domains is provided in the Resource Guide)