PDB is a resource for studying Biological Macromolecules
The PDB archive contains information about experimentally-determined structures of proteins, nucleic acids, and complex assemblies. As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards.
The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Here I attach an example to describe more on PDB through the example of tryptophan. The more specific name for this example is 2KEP. This is the solution structure of XcpT, the main component of the type 2 secretion system of Pseudomonas aeruginosa.
You can link to this website to have more details information about PDB and this example of '2KEP'..