P.d.b. Link

The archive uses several formats to store 3D coordinates and experimental data: Guide to Understanding PDB Data: Biological Assemblies

: Every entry is assigned a unique four-letter/number code (e.g., 4HHB for hemoglobin). P.D.B.

: An "Entity" is a unique molecule (like a specific protein chain), while an "Instance" (or Chain ID) is a specific copy of that molecule within the structure (e.g., Chain A and Chain B). 2. Standard File Formats The archive uses several formats to store 3D