PDBe Get Uniprot Mappings

Get UniProt-to-PDB chain mappings for a PDB structure from the PDBe Graph API. For each UniProt accession represented in the structure, returns all chain mappings with residue-level alignment (UniProt start/end, PDB start/end, identity, coverage). Essential for understanding which proteins are in a crystal structure and how they map to UniProt reference sequences. Example: 4HHB returns P69905 (HBA_HUMAN) mapped to chains A,C and P68871 (HBB_HUMAN) mapped to chains B,D.